WO1996010367A1 - Systems and methods for ablating body tissue - Google Patents

Systems and methods for ablating body tissue Download PDF

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Publication number
WO1996010367A1
WO1996010367A1 PCT/US1995/012257 US9512257W WO9610367A1 WO 1996010367 A1 WO1996010367 A1 WO 1996010367A1 US 9512257 W US9512257 W US 9512257W WO 9610367 A1 WO9610367 A1 WO 9610367A1
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WIPO (PCT)
Prior art keywords
tissue
housing
tissue region
catheter
ablation
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Application number
PCT/US1995/012257
Other languages
French (fr)
Inventor
Michael D. Lesh
Stuart D. Edwards
Original Assignee
The Regents Of The University Of California
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Filing date
Publication date
Application filed by The Regents Of The University Of California filed Critical The Regents Of The University Of California
Priority to AU36845/95A priority Critical patent/AU3684595A/en
Publication of WO1996010367A1 publication Critical patent/WO1996010367A1/en

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Classifications

    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/04Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
    • A61B18/12Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
    • A61B18/14Probes or electrodes therefor
    • A61B18/1492Probes or electrodes therefor having a flexible, catheter-like structure, e.g. for heart ablation
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/04Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
    • A61B18/12Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
    • A61B18/14Probes or electrodes therefor
    • A61B18/1477Needle-like probes
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00Surgical instruments, devices or methods, e.g. tourniquets
    • A61B2017/00017Electrical control of surgical instruments
    • A61B2017/00022Sensing or detecting at the treatment site
    • A61B2017/00084Temperature
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00Surgical instruments, devices or methods, e.g. tourniquets
    • A61B17/00234Surgical instruments, devices or methods, e.g. tourniquets for minimally invasive surgery
    • A61B2017/00292Surgical instruments, devices or methods, e.g. tourniquets for minimally invasive surgery mounted on or guided by flexible, e.g. catheter-like, means
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00053Mechanical features of the instrument of device
    • A61B2018/00273Anchoring means for temporary attachment of a device to tissue
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00636Sensing and controlling the application of energy
    • A61B2018/00773Sensed parameters
    • A61B2018/00791Temperature
    • A61B2018/00815Temperature measured by a thermistor
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/04Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
    • A61B18/12Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
    • A61B18/14Probes or electrodes therefor
    • A61B2018/1405Electrodes having a specific shape
    • A61B2018/1425Needle
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/04Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
    • A61B18/12Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
    • A61B18/14Probes or electrodes therefor
    • A61B2018/1405Electrodes having a specific shape
    • A61B2018/1435Spiral
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61MDEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M25/00Catheters; Hollow probes
    • A61M25/0067Catheters; Hollow probes characterised by the distal end, e.g. tips
    • A61M25/0068Static characteristics of the catheter tip, e.g. shape, atraumatic tip, curved tip or tip structure
    • A61M25/007Side holes, e.g. their profiles or arrangements; Provisions to keep side holes unblocked
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61NELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N7/00Ultrasound therapy
    • A61N7/02Localised ultrasound hyperthermia

Definitions

  • Arrhythmias refer to tachycardias at rates exceeding 100 beats per minute for a duration of at least 3 beats. Sometimes no treatment is required, such as in the tachycardia following a physiologic response to stress or exer ⁇ cise. However, in some cases, treatment is required to alleviate symptoms or to prolong the patient's life expectancy. 0367 PCMJS95/12257
  • Treatment by abla ⁇ tion involves destruction of a portion of cardiac tissue which is functioning abnormally electrically.
  • the heat Normally the heat possesses an intrinsic pacemaker function in the sinoatrial (SA) node which is in the right atrium, adjacent to the entrance of the superior vena cava.
  • SA sinoatrial
  • the right atrium is one of four anatomic chambers of the heart.
  • the other chambers are the right ventricle, the left atrium, and the left ventricle.
  • the superior vena cava is a major source of venous return to the heart.
  • the SA node is an area of specialized cardiac tissue called Purkinje cells and which measures roughly 1- 1/2 centimeters by about 2-1/2 millimeters.
  • An electrical impulse normally exits from the SA node and travels across the atrium until it reaches the atrioventricular (AV) node.
  • the AV node is located in the right atrium near the ventricle. Emerging from the AV node is a specialized bundle of cardiac muscle cells which originate at the AV node in the interatrial septum. This "bundle of His" passes through the atrioventricular junction and later divides into left and right branches which supply the left and right ventricles. The left and right bundles further give rise to branches which become the so-called distal His-Purkinje system, which extends throughout both ventricles.
  • an impulse orig- inates intrinsically at the SA node, transmits through the atrium and is modified by the AV node.
  • the AV node passes the modified impulse throughout the left and right ventricles via the His-Purkinje system to result in a coordinated heartbeat at a normal rate.
  • the heart rate in ad ⁇ dition to the intrinsic conduction system.
  • the heart rate will respond to phys ⁇ iologic parameters such as stress, exercise, oxygen tension and vagal influences.
  • an abnormal heartbeat such as an abnormal tachycardia.
  • One group of such causes relates to abnormalities in the heart's conduction system.
  • ectopic or abnormally posi- tioned nodes may take over the normal function of a node such as the SA or AV node.
  • one of the normal nodes may be diseased such as from ischemic heart disease, coronary artery disease or congenital reasons.
  • a defect can exist in an important part of the conduction system such as the bundle of His or one of the bundle branches supplying the ventricles.
  • Treatment of abnormal tachycardias arising from ectopic foci or so-called ectopic pacemakers can include pharmacologic therapy or ablative ther ⁇ apy.
  • the ablative therapy may be accomplished by percutaneous insertion of a catheter or by an open surgical cardiac procedure.
  • Cardiac arrhythmias may be abolished by ablating the tissue responsible for the genesis and perpetuation of the arrhythmias.
  • Steerable ablation catheters using radio frequency (RF) energy are known.
  • the RF energy can be directed to the area to be ablated and causes destruction of tissue by heat.
  • direct infusion of ethanol has been performed during open heart surgery.
  • Ethanol has also been infused into coronary arteries to ablate a focus such as a ventricular arrhythmia focus or the AV node. Unfortunately, this tends to result in a fairly large region of cardiac tissue death or myocardial infarction. With transarterial infusion there is difficulty in precisely controlling the location and extent of the ablation.
  • the present invention is directed to sys ⁇ tems and methods for ablating tissue in the body.
  • the device comprises a catheter tube having a control end and a probe end.
  • the probe end in ⁇ cludes a housing having a port.
  • An element is lo ⁇ cated within the housing.
  • the element is movable between a first position confined within the housing and a second position extending through the port outside the housing.
  • the element has a distal tip adapted to penetrate a tissue region during movement between the first and second position.
  • the element comprises either an electrode for emitting electro ⁇ magnetic radio frequency energy into the tissue re- gion, or a cannula with an interior lumen for con ⁇ veying fluid to and from the tissue region, or a sensor for sensing temperature conditions in the tissue region.
  • the element has a threaded exterior with a distal tip adapted to pene- trate a tissue region in response to rotation of the element during movement between the first and second position.
  • Another aspect of the invention provides a method for ablating tissue within the body.
  • the method introduces a catheter tube having a control end and a probe end in the body.
  • the probe end in ⁇ cludes a housing and an element within the housing movable between a first position confined within the housing and a second position extending outside the housing.
  • the element has a distal tip adapted to penetrate a tissue region during movement between the first and second position.
  • the element is located in the first position within the housing.
  • the method places the probe end in contact with a tissue region and moves the element from the first position to the second position to penetrate the contacted tissue region.
  • the method ablates the tissue region, while the element penetrates it, by either emitting electromagnetic radio frequency en ⁇ ergy through the element into the tissue region or conveying ablation fluid through a lumen in the ele ⁇ ment for discharge into the tissue region.
  • the catheters in one preferred embodiment of the inven ⁇ tion have an elongated flexible body and a tissue ablation assembly having a tissue ablation tip at the distal end of the body. The distal end of the catheter is introduced into a cardiac chamber (or other body region) including the tissue to be ab ⁇ lated.
  • the catheter may be equipped for standard arrhythmia mapping, for example multiple electrodes may be present on the outside of the catheter for recording endocardial electrograms.
  • the catheter may include a visualization assembly at the distal end of the body.
  • the visualization as ⁇ sembly is used to position the tip of the catheter adjacent the tissue to be ablated.
  • Catheters com- prising visualization and ablation means are de ⁇ scribed in copending application Serial No. 08/099,995, Filed July 30, 1993, entitled “Cardiac Imaging and Ablation Catheter,” which is incorpo ⁇ rated herein by reference.
  • the tissue ablation as ⁇ sembly comprises a hollow infusion needle which can be extended or withdrawn from the distal end of the catheter.
  • the hollow infusion needles of the inven ⁇ tion have a securing element configured to engage tissue when the needle is at least partially insert ⁇ ed into the tissue to stop recoil and help prevent inadvertent removal of the needle from the tissue.
  • the securing element can be configured into the form of corkscrew or threads surrounding a straight nee- die.
  • the securing element can be configured as a plurality of pre-curved needles, which curve towards or away from the longitudinal axis of the catheter.
  • the pre-curved needles can also be used to deliver ablation compounds if de- sired. Other structures, such as barbs, could also be used as the securing element.
  • the hollow infu ⁇ sion needle is preferably a corkscrew-shaped needle, with a tight curl.
  • the distance between turns is preferably about 0.5 mm or less.
  • the catheter When used to ablate tissue the catheter can be used with a conventional ablation compound such as alcohol (e.g., ethanol) , collagen, phenol, carbon dioxide and the like.
  • a conventional ablation compound such as alcohol (e.g., ethanol)
  • the solution may comprise various components for other purposes as well.
  • an echocontrast agent for echo imaging may be included.
  • Collagen can be bound to an iodinated molecule to make it radiodense.
  • the catheters of the invention can be used to introduce desired poly- nucleotides to the target tissue.
  • fluoroscopy can be used to visu ⁇ alize the chambers of the heart.
  • Fluoroscopy uses roentgen rays (X-rays) and includes use of a spe ⁇ cialized screen which projects the shadows of the X- rays passing through the heart.
  • Injectable contrast agents to enhance the fluoroscopic picture are well known in the art and are not described in detail here.
  • the catheter is placed in an artery or a vein of the patient depending on whether the left (ventricle and/or atrium) or right (ventri ⁇ cle and/or atrium) side of the heart is to be ex ⁇ plored and portions thereof ablated.
  • an artery or vein in the groin such as one of the femo- ral vessels is selected for catheterization.
  • the catheter is passed via the blood vessel to the vena cava or aorta, also depending on whether the right or left side of the heart is to be catheterized, and from there into the appropriate atrium and/or ven- tricle.
  • the catheter is generally steerable and it is positioned against an endocardial region of in ⁇ terest.
  • the catheter typically includes a means for sensing the electrical impulses originating in the heart.
  • the electrode cath- eter can provide a number of electrocardiogram read ⁇ ings from different areas of the internal aspects of the heart chambers. These various readings are cor ⁇ related to provide an electrophysiologic map of the heart including notation of normal or abnormal fea ⁇ tures of the heart's conduction system. Once the electrophysiologic map is produced, an area may be selected for ablation.
  • the sus- pect area is temporarily suppressed or deadened with a substance such as lidocaine or iced saline solu ⁇ tion. Subsequently the area is remapped and heart reevaluated to determine if the temporary measure has provided some electrophysiologic improvement. If improvement has occurred, then the clinician ma proceed with permanent ablation typically using eth- anol.
  • the present invention pro ⁇ vides the novel combination of tissue ablation and tissue imaging in a single catheter to permit abla ⁇ tion of tissue to be properly accomplished by the correct selection of the ablation site and monitor ⁇ ing and controlling the ablation of the tissue being destroyed.
  • the invention is preferably used with imaging ultrasonic transceivers in an ablation cath ⁇ eter to provide real time assessment of lesion vol ⁇ ume and to monitor the tissue being ablated.
  • one or more A-mode ultrasonic crystals can be used.
  • a visualization means of the invention may be either an imaging or an A-mode ultrasonic device.
  • One or more transponder can also be used to assist in localizing the catheter tip.
  • the catheters in one preferred embodiment of the invention have abla- tion elements that move outward to penetrate tissue from the side of the probe.
  • the ablation elements either emit electromagnetic radio frequency energy to heat and thermally destroy the penetrated tissue or convey an ablation fluid to chemically destroy the penetrated tissue.
  • Fig. 1 is an overall view of a catheter made according to the invention
  • Fig. 2 is an enlarged, simplified cross- sectional view of the distal end of the flexible body of Fig. 1;
  • Fig. 3 is an enlarged, schematic cross-sec ⁇ tional view of the distal end of the flexible body of Fig. 1 illustrating the general locations of the tip electrode, ultrasonic transducer, and ring elec ⁇ trodes;
  • Fig. 4 is an overall view of an alternative catheter made according to the invention.
  • Fig. 5 is an enlarged, simplified cross- sectional view of the tip and the catheter of Fig. 4, shown with a hollow needle retracted;
  • Fig. 6 is an external view of the tip of Fig. 5 with the hollow needle extended;
  • Fig. 7 is an enlarged view of the needle driver and infusion port mounted to the handle of Fig. 4
  • Fig. 8 is an enlarged, simplified cross- sectional view of the tip of a catheter with a hol ⁇ low needle retracted;
  • Fig. 9 illustrates the handle assembly of a catheter of the invention.
  • Fig. 10A is an enlarged, simplified cross- sectional view of the tip of a catheter with the anchoring needles and hollow needle in the extended position;
  • Fig. 11A is an enlarged, simplified cross- sectional view of the tip of a catheter with the anchoring/infusion needles in the extended position;
  • Fig. 11B is an end view of catheter tip in Fig. 11A;
  • Fig. 12 is an end view of a catheter tip with 10 anchoring/infusion needles
  • Fig. 13A is an enlarged, simplified cross- sectional view of the tip of a catheter showing the triggering mechanism with the anchoring/infusion needles in the retracted position;
  • Fig. 13B is an enlarged, simplified cross- sectional view of the tip of a catheter showing the triggering mechanism with the anchoring/infusion needles in the extended position;
  • Fig. 14 illustrates the handle assembly of a catheter of the invention showing the trigger for releasing and retracting the anchoring needles
  • Fig. 15 is a catheter carrying at its dis- tal end a multi-function probe that embodies the features of the invention
  • Fig. 16 is an enlarged section view of the multi-function probe, which the catheter shown in
  • Fig. 15 carries at its distal end, with the associ- ated screw ablation element located in its retracted position;
  • Fig. 17 is an enlarged view of the multi ⁇ function probe with the associated screw ablation element located in its extended position
  • Fig. 18 is a perspective view of the screw ablation element shown in Figs. 16 and 17 deployed in its extended position in tissue;
  • Figs. 19A, B, C, and D are diagrammatic views showing the use of the multi-function probe shown in Fig. 15 in ablating tissue in the left ven ⁇ tricle of the heart;
  • Fig. 20 is an ablation element suited for the treatment of benign prostatic hypertrophy, with its associated expandable ablation electrodes col- lapsed and its associated penetrating ablation elec ⁇ trodes retracted;
  • Fig. 21 is a top view of the ablation ele ⁇ ment shown in Fig. 20;
  • Fig. 22 is the ablation element shown in Fig. 20, with its associated expandable ablation electrodes inflated and its associated penetrating ablation electrodes extended and penetrating tissue;
  • Fig. 23 is a top view of the ablation ele ⁇ ment shown in Fig. 22;
  • Fig. 24 is a diagrammatic view of the abla ⁇ tion element when deployed for use in the prostrate region of the body. Description of the Preferred f-nfaa-iiment
  • Fig. 1 illustrates a catheter 2 having a handle 4 from which a flexible body 6 extends.
  • Flexible body 6 extends from one end 8 of handle 4 while ultrasonic cable 10 and a combination elec ⁇ trode/thermistor cable 12 extend from the other end 14 of handle 4.
  • Distal end 16 of flexible body 6 is steerable, as suggested by the dashed lines 18 in Fig. 1, in a conventional manner using a steering lever 20 mounted to handle 4.
  • Lever 20 which con ⁇ trols one or more steering cables 22, see Fig. 2, as is conventional.
  • Distal end 16 has an RF transmit- ting tip 24 secured thereto. Transmitting tip 24 is connected to an appropriate RF energy source, not shown, through lead 26 which extends along flexible body 6, through handle 4 and through combined cable 12.
  • Tip 24 has a pair of axially extending bores 28, 30 formed from its distal end 32. Bore 28 is used to house an ultrasonic transducer 34 while bore 30 is used to house a thermistor 36. Transduc ⁇ er 34 is surrounded by a thermal insulating sleeve 38, typically made of insulating material such as polyimide. The base 40 of transducer 34 has a lead 41 extending from transducer 34, along flexible body 6, through handle 4 and through ultrasonic cable 10. The ultrasonic transducer comprises a piezoelectric crystal capable of operating at a standard frequen ⁇ cy * typically from about 5 to about 5 MHz.
  • the crystal is formed from standard materials such as barium titanate, cinnabar, or zirconate-titanate.
  • the transducer 34 generates an ultrasonic pulse in response to electrical impulses delivered through lead 41. Ultrasonic echoes are then received by the ultrasonic transducer 34 which generates electrical signals which are delivered to the receiving unit (not shown) .
  • the transducer is connected to conven- tional transmitting and receiving units which in ⁇ clude the circuitry necessary for interpreting the ultrasonic information and displaying the informa ⁇ tion on a visual display. Signal processing may take advantage of change in tissue density or tex- ture as correlated with lesion depth.
  • the ultrason ⁇ ic signal can be visualized on a two dimensional echocardiograph or using non-imaging A-mode.
  • transducer 34 Base 40 of transducer 34 is sealed with a UN potting adhesive 42, such as Tough Medical Bonder made by Loctite, to provide both thermal and elec- trical insulation.
  • the catheter also comprises an ultrasonic transponder 44, shown schematically in Fig. 3, spaced about 2.5 mm from RF transmitting tip 24 at the distal end 16 of body 6.
  • Transponder 44 is used to help in localization of the catheter tip as is known in the art and described in Langberg et al., JACC 12:218-223 (1988). In alternate embodi ⁇ ments, multiple transponders can be used to help with assessing catheter tip orientation as well. In the embodiment of Figs.
  • catheter 2 also includes three ring electrodes 46, 47, 48 positioned in a proximal direction, that is towards handle 4 relative to tip electrode 24 and transducer 44. Electrodes 46-48 (spaced 2.5 mm apart) are used to record electrical signals pro ⁇ quizd by the heart (electrocardiograms) for endocar ⁇ dial mapping using a multichannel EKG machine as is known in the art.
  • Thermistor 36 is coupled to com ⁇ bination cable 12 through a lead 50 extending from thermistor 36, to flexible body 6, through handle 4 and into combination cable 12. Thermistor 36 is used to provide information about the temperature of the tissue at the distal end 32 of tip 24.
  • the above-discussed apparatus used to create ultrasonic visualization of the tis ⁇ sue to be ablated is generally conventional.
  • the ultrasonic visualization means may be used for either imaging or A-mode.
  • One such ultrasonic imaging system is sold by Cardiovascular Imaging Systems of Sunnyvale, California.
  • the RF ablation system, used to ablate the tis ⁇ sue is also generally conventional, such as is sold, for example, by EP Technologies, Inc. of Sunnyvale, California. What is novel is incorporat ⁇ ing both the imaging and ablation structure into a single catheter which permits real time visualiza ⁇ tion and accurate positioning of the RF transmitter tip 24 with the precise location to be ablated.
  • the amount or volume of tissue ablated can thus be con ⁇ stantly monitored during the procedure so that nei ⁇ ther too little or too much tissue is ablated for maximum control and effectiveness.
  • the use of tem- perature monitoring using thermistor 36 is also gen ⁇ erally conventional as well, but not in conjunction with an ultrasonic imaging assembly.
  • microwave ra ⁇ diation, laser energy, cryoblation or endocardial injection/infusion, for example, can be used in con ⁇ junction with ultrasonic transducer 34.
  • catheter 2 proceeds generally as follows. Distal end 16 of body 6 is directed to the appropriate site using conventional techniques and steering lever 20. Visualization of the tissue to be ablated and localization of the tip 24 is provid ⁇ ed by ultrasonic transducer 34, ultrasonic tran ⁇ sponder 44, and associated leads and cables coupled to a conventional ultrasonic imaging console, not shown.
  • ultrasonic transducer 34 When tip 24 is at the site of the tissue to be ablated, RF generator, not shown, coupled to combination cable 12, is activated to produce RF radiation at tip 24 to ablate the tissue. The ab ⁇ lation is monitored by ultrasonic transducer 34 as well as thermistor 36 to help ensure that the proper volume of tissue is ablated.
  • catheter 2 including an RF transmitter tip 24
  • the catheter could use an ablation fluid infusion tip similar to that shown in Figs. 4-7.
  • the suspect area can be temporarily sup ⁇ pressed to deadened using catheter 60 using lido ⁇ caine or iced saline solution, as discussed in the Background section above.
  • Catheter 60 includes a handle 62 from which a flexible body 64 extends.
  • Handle 62 includes a steering lever 65 and combination infu- sion port 66 and needle driver 68 at the distal end 70 of handle 62.
  • a pair of cables 72 extend from the proximal end 74 of handle 62.
  • a pair of cables 72 extend from the proximal end 74 of handle 62.
  • the distal end 76 of flexible body 64 has a tip as- sembly 78 mounted thereto.
  • Tip assembly 78 includes mapping electrodes 80 connected to wires 82 which extend down flexible body 64, through handle 62 and to cables 72.
  • Mapping electrodes 80 provide the user with a nonvisual indication of where tip assem- bly is by monitoring the electro-activity of the heart muscle, as is conventional. Electrodes 80 are electrically isolated from the remainder of tip as ⁇ sembly 78 by an insulating sleeve 84.
  • a hollow needle 86 is slidably mounted within a second insulating sleeve 88 housed within insulating sleeve 84.
  • the needle may be formed from standard metal alloys such as titanium alloy, stain ⁇ less steel, and cobalt steel.
  • the needle 86 is a corkscrew-shaped needle used to inject ablating liq- uid into tissue and secure the needle to the tissue.
  • Other designs of hollow needles, including the use of barbs on a straight or curved needle, can be used as well. While hollow needle 86 is shown used with a generally conventional mapping electrode type of catheter, it could be used with an ultrasonic visu- alization assembly as shown in Figs. 1-3, as well as other types of visualization assemblies.
  • a central bore 90 of hollow needle 86 is coupled to infusion port 66 by an infusion fluid tube 92 which extends along flexible body 674, through needle driver 68 and to infusion port 66.
  • Threaded needle driver 68 is connected to a tip ex ⁇ tension 94 so that rotating needle driver 68 causes tip extension 94 to rotate about the axis 95 of nee- die 86 and to move axially within flexible body 64.
  • This causes hollow needle 86 to rotate about axis 95 and to move axially within sleeve 88 from the re ⁇ tracted position of Fig. 5 to the extended position of Fig. 6.
  • Rotating needle driver 68 also rotates hol ⁇ low needle 86 so that it bores into the tissue to be ablated.
  • an appropriate liquid such as ethanol
  • infusion port 66 When properly in position, an appropriate liquid, such as ethanol, can be infused into the tissue to be ablated through infusion port 66, in- fusion fluid tube 92, hollow needle 86, and into the tissue. Since the tip 100 of hollow needle 86 is buried within the tissue to be ablated, the operator is assured that the ablation liquid is delivered to the proper place while minimizing ablation of sur- rounding tissue.
  • the needle is typically used to inject an ablation liquid endocardially to produce a more cir ⁇ cumscribed lesion than that possible using prior art infusion techniques.
  • the needle is designed such that it can be imbedded in and secured to the tissue to be treated.
  • ablation of cardiac tissue is a preferred use of the catheters of the invention, they can be used to inject desired compositions for a wide variety of uses.
  • Virtually any therapeutic compound can be delivered intracardially using the catheters of the invention.
  • the cath ⁇ eters can be used to deliver compositions comprising modified genes to cardiac or other tissue for use in gene therapy protocols.
  • Methods for introducing a variety of desired polynucleotides to target cells using, for example, retroviral vectors are well known. Examples of sequences that may be introduced include antisense polynucleotides to control expres- sion of target endogenous genes.
  • genes encoding toxins can be targeted for delivery to can ⁇ cer cells in tumors.
  • homolo ⁇ gous targeting constructs can be used to replace an endogenous target gene.
  • Methods and materials for preparing such constructs are known by those of skill in the art and are described in various refer ⁇ ences. See, e.g., Capecchi, Science 244:1288 (1989) .
  • ap ⁇ proaches typically involve placement of the desired cells on or within matrices or membranes which pre ⁇ vent the host immune system from attacking the cells but allow nutrients and waste to pass to and from the cells (see, Langer et al., Science 260:920-925 (1993)).
  • sinus node cells can be im ⁇ planted in a desired location to treat disorders in impulse formation and/or transmission that lead to bradycardia.
  • Fig. 8 the distal end 102 of a catheter of the present invention is shown.
  • the hollow corkscrew infusion needle 104 is movably positioned within flexible distal tube 106.
  • the flexible tube 106 allows movement of the distal end 102 in response to the steering mechanism 112.
  • the steering mechanism 112 is conventional and functions as is known in the art.
  • the distal end 102 also comprises mapping electrodes 108 which monitor elec ⁇ tro activity of the heart muscle as described above.
  • the mapping electrodes are connected through signal wires 111 to standard multichannel EKG machine as is known in the art.
  • the braided torque tube 114 is connected to the inside diameter of the infusion needle 104 and provides means for rotating the infusion needle 104 about the longitudinal axis 105 of the catheter and moving the needle 104 axially within the distal tube 106.
  • the braided torque tube 114 consists of stan ⁇ dard flexible tubing overlapped with a wire braid which stiffens the tube and allows torquing of the tube to rotate the needle 104.
  • Fig. 9 shows the handle assembly 115 of a catheter of the present invention.
  • the braided tube 114 is connected to an infusion needle ad- vance/retract knob 116 by which the user controls axial movement of the infusion needle 104.
  • a female luer lock infusion port is positioned on the ad ⁇ vance/retract knob 116.
  • a standard strain relief means 118 prevents kinking of the flexible tube 119.
  • a handle 120 secured to the cathe ⁇ ter through front handle support 122 and rear handle support 124.
  • the handle assembly 115 is attached to a standard steering/mapping catheter handle 130 as is conventional and signal wires 132 are connected to the appropriate receiving units.
  • Figs. 10A through 10C show the distal end 134 of a catheter comprising an infusion needle 136 connected to a braided torque tube 138 as described above.
  • the distal tube 142 also comprises an elas- to eric seal 152 made from standard materials well known to those of skill in the art.
  • the elastomeric seal 152 provides a seal for the distal tube 142 and prevents blood from flowing into the lumen of the catheter.
  • the infusion needle 136 is coated with a compound such as mold release, to fa ⁇ cilitate movement of the needle through the elasto ⁇ meric seal 152.
  • a set of spring loaded pre-curved anchoring needles 144 positioned near the outer edge of the distal tube 142.
  • the anchoring needles are attached to a shut ⁇ tle 150 and compression spring 146 which are trig ⁇ gered through pull wires 148 through a trigger de ⁇ vice on the handle.
  • the function of the trigger device is shown more fully in Figs 13A, 13B and 14.
  • Fig. 10B shows the extended anchoring nee ⁇ dles 144 after the triggering device has released the shuttle 150 and compression spring 146.
  • This mechanism permits the distal end of the catheter to be attached in an almost instantaneous fashion and eliminates the effects of cardiac motion on the at ⁇ tachment procedure.
  • Fig. 10C is an end view of the distal end 134 showing the position of the pre- curved anchoring needles 144 after release.
  • the anchoring needles 144 are curved towards the longitudinal axis of the cathe ⁇ ter.
  • the anchoring needles 114 can be curved towards or away from the longitudinal axis.
  • FIG. 11A and 11B show a further embodiment of the catheter comprising anchoring needles 162 which are used for infusion as well as anchoring.
  • the needles 162 are connected to infusion channel 160 through which the ablation liq ⁇ uid or other compound is delivered to the infusion needles 162.
  • the infusion needles 162 are shown in the extended position after the shuttle 166 and com ⁇ pression spring 164 have moved the needles 162 axi ⁇ ally through the distal tube 156.
  • map electrodes 152 can be used to cre- ate an electro physiological map of the tissue.
  • Braided tube 158 is used to anchor the compression spring 164.
  • the infusion needles are curved outward as well as inward in this embodiment ( Figure 11B) .
  • Fig. 12 is an end view of the distal end 168 of a catheter of the invention showing the ar ⁇ rangement of infusion needles 170 in which five nee ⁇ dles project away from the longitudinal axis and five project toward the
  • Figs. 13A and 13B illustrate the trigger assembly by which the pre-curved needles 200 ar re ⁇ leased from the distal end 202 of the catheters of the present invention.
  • Fig. 13A shows the pre- curved needles 200 in the retracted position within the flexible distal tube 204.
  • the pre-curved nee- dies 200 are attached to the shuttle 206 which is held in place by three trigger tabs 208, two of which are illustrated in Fig. 13A.
  • the trigger tabs 208 are permanently fixed to the front stop 210 and pre-loaded against the inner diameter 212 of the distal tube 204.
  • the pre-curved needles 200 are fluidly con ⁇ nected to infusion channel 214, which enters the flexible distal tube distal 204, through braided tube 211.
  • Map electrodes 216 are used to create an electro physiological map of the heart as described.
  • Fig. 13B shows the pre-curved needles 200 in the extended position after the trigger tabs 208 have been pulled towards the longitude axis of the catheter by the trigger pull wires 220.
  • the shuttle 206 is released and the compression spring 222 drives the shuttle 206 and needles 200 rapidly towards the distal tip of the catheter.
  • the inertia of the catheter body prevents the tip from withdrawing and needles 200 ar subse ⁇ quently driven into the target tissue.
  • Fig. 13B also shows the position of the trigger tabs 208 on the inner diameter of the shuttle 206 after the shuttle 206 has moved forward. After use the shut ⁇ tle pull wires 218 are activated to pull the pre- curved needles 200 to the retracted position.
  • Fig. 1 A shows the handle assembly 230 com ⁇ prising a handle body 232 from which this position and ablation tip steering lever 234.
  • the handle body 232 comprises a needle trigger 236 which is shown in both the cocked and fired (dashed lines) positions.
  • the distal end of the trigger wires 238 are attached between the distal end 240 and the piv- ot point 242 to insure the wires 238 are pulled when the lever is pulled.
  • the retractor 244 is shown in the cocked and fired (dashed lines) positions, as well.
  • the pull wires 244 are attached between the pivot point 246 and the distal end of the retractor 248 as for the trigger.
  • the handle assembly in ⁇ cludes a lead 250 which allows for connection to appropriate ablation compound as described above.
  • Fig. 15 shows a catheter 300 having at its distal end a multi-function probe assembly 302 capa- ble of sensing physiological events in endocardial and myocardial tissue, thermally stunning endocardi ⁇ al and myocardial tissue, and ablating myocardial tissue.
  • the catheter 300 includes a conventional flexible guide coil 312 within a catheter tube 304 made of an electrically non-conducting material, like polyurethane (see Fig. 16) .
  • the proximal end of the catheter tube 304 carries a handle 306.
  • the handle 306 allows the physician to remotely control the probe assembly 302 in the body.
  • the distal end of the catheter tube 304 is steerable by conventional means, thereby also steering the probe assembly 302.
  • the handle 306 carries a steering lever 308 attached by steering wires (not shown) to steering springs 310 in the distal end of the catheter tube 304 (see Fig. 16) .
  • the probe assembly 302 includes electrodes 314 and 316 that sense phys ⁇ iological events in heart tissue.
  • the electrodes 314 senses monophasic action potentials (MAP) in conventional fashion.
  • the electrode 316 comprises the reference electrode for the MAP electrode 314.
  • the probe assembly 302 houses an ablation electrode 318.
  • the ablation electrode 318 is made from a biocompatible material known to conduct elec ⁇ tricity, like platinum or stainless steel.
  • the electrode 318 is formed in the shape of a hollow screw.
  • the electrode 318 will thus be called a "screw electrode.”
  • the screw electrode 318 includes a tapered or pointed exterior surface 320, which is sharpened for penetration of tissue.
  • the surface 320 is also threaded, like, for example, a wood screw, for advancement into tissue when rotated.
  • a sleeve 322 guides and directs movement of the screw electrode 318 along an axial path within the probe assembly 302.
  • the sleeve 322 is made of an electrically non-conductive material (like poly ⁇ urethane) to thereby electrically insulate the screw electrode 318 from the MAP electrodes 314.
  • the base 324 of the screw electrode 318 is attached to a tip extending shaft 326.
  • the shaft 326 passes through the guide coil 312 to a screw extend ⁇ er 328 on the handle 306 (see Fig.15).
  • Rotation of the screw extender 328 by the physician is translat ⁇ ed by the shaft 326 into rotation and axial advance ⁇ ment of the screw electrode 318, which the sleeve 322 guides to move the screw electrode 318 between a retracted position within the probe assembly 302 (as Fig. 16 shows) and an extended position outside the probe assembly 302 (as Fig. 17 shows) .
  • Insulated wires 330, 332, and 334 pass through the guide coil 312 for electrical connection to components of the probe assembly 302.
  • the wires 330 and 332 are electrically coupled to the MAP electrodes 314 and the MAP reference electrode 316.
  • the wire 334 is electrically coupled to the screw electrode 318.
  • the proximal ends of the wires 330, 332, and 334 pass into the handle 306.
  • the wires 330, 332, and 334 are electrically coupled within the handle 306 to external connectors 336.
  • the connec ⁇ tors 336 plug into a source of energy known to ther ⁇ mally destroy (i.e., ablate) body tissue.
  • microwave energy and other frequencies of elec ⁇ tromagnetic radio frequency (RF) energy (lying in the frequency range of from about 500 kHz to about 2.5 GHz) are known to ablate body tissue.
  • the wire 334 conveys the selected energy to the screw elec- trode 318 for transmission through tissue, when used in association with a conventional external patch electrode (called an "indifferent" electrode) at ⁇ tached to the patient's skin or to a grounding plate that the patient lies upon.
  • the connectors 336 also plug into an external conventional device for pro ⁇ cessing the MAP signals, which are conveyed by the wires 330 and 332.
  • the screw electrode 318 also includes an interior passage or lumen 338 which communicates with an injection fluid tube 340.
  • the injection fluid tube 340 extends through the guide coil 312 to an injection site 342 carried on the handle 306 (see Fig. 15) .
  • the interior passage 338 communicates with outlets 344 in the exterior surface 320 of the screw electrode 318 for discharging fluid carried by the injection fluid tube 340.
  • the physician deploys the distal probe assembly 302 into the contact with tissue 346, which Fig. 19A diagrammatically shows to be within the left ventricle of the heart.
  • tissue 346 which Fig. 19A diagrammatically shows to be within the left ventricle of the heart.
  • the physician uses the MAP electrodes 314 to measure MAP signals to locate an early acti ⁇ vation site (EAS) using conventional techniques.
  • EAS early acti ⁇ vation site
  • the physician ro- tates the screw extender 328 to advance the screw electrode 318 into heart tissue where the EAS is found (as Figs. 18 and 19B show) .
  • the physician injects very cold (iced) saline with a syringe 348 (see Fig. 1) through the injection site 342.
  • the outlets 344 on the screw electrode 318 discharge the cold saline into the surrounding tissue 346 (shown by arrows in Figs. 18 and 19B) .
  • the physician can introduce carbon dioxide through the injection site 342, which results in cooling (through Joule-Thompson expansion) at the outlets 344 of the screw electrode 318.
  • the cold temperature temporarily stuns the surrounding tissue 346.
  • the stunning electrically isolates the tissue from the surrounding myocardium, during which time the tissue physiology emulates dead tissue. Confirming that a given tacharrhymia cannot be induced when tissue 346 is stunned vali ⁇ dates that a correct site for ablation has been lo ⁇ cated.
  • the physician applies ablation energy to the screw electrode 318 for transmission into surrounding tissue (as the wave lines in Fig. 19C show) .
  • the ablation energy reaches myocardial tissue significantly below the endocardium, deeper than a surface ablation elec ⁇ trode could reach.
  • the phy ⁇ sician can inject alcohol through the injection site 342, which the outlets 344 on the screw electrode 318 discharge into the surrounding tissue area. The alcohol ablates the tissue by chemical means rather than by heating, as RF energy does.
  • the physician can validate the elimination of arrhythmia following ablation by reviewing endo ⁇ cardial electrograms. Once validation occurs, the physician rotates the screw extender 328 to withdraw the screw electrode 318 into its retracted position. The physician can withdraw the assembly 302 from the heart, or repeat the above steps, as necessary, to locate and eliminate multiple arrhythmia sources.
  • Figs. 20 to 24 show an ablation element or probe 400 suited for the treatment of benign pros- tatic hypertrophy or hyperplasia (BPH) .
  • the ablation element 400 includes a body 402 attachable to the end of a conventional catheter tube 404 for inser ⁇ tion through the urethra (see Fig. 24) into contact with prostrate tissue 408.
  • the catheter tube 404 itself can be like that shown in Figs. 15 and 16, with a flexible guide coil 312 running through it and a handle 306 at its proximal end.
  • the body 402 of the ablation element 400 is made of an electri- cally non-conducting material conventionally used for medical use catheters, for example polyurethane.
  • the diameter of the body 402 is about 20 Fr. , or larger.
  • the element 400 includes near its distal end 410 one or more expandable bellows 412.
  • the bel ⁇ lows 412 are made of a biocompatible elastomeric material, like silicone rubber.
  • the bellows 412 are attached by upper and lower fluid-tight lock bands 414 circumferentially about the body 402.
  • Fluid lines 416 extend within the body 402 and communicate with each bellows 412.
  • the fluid lines 416 pass through the flexible guide coil 312 and exit the proximal end of the catheter tube 404 for attachment to an external source of saline solu- tion (or another physiologically compatible liquid) .
  • the fluid lines 416 convey the solution from the external source into the bellows 412. As Fig. 22 shows, the fluid expands the bellows 412, urging them into contact with tissue 408.
  • the fluid-filled bellows 412 stabilize the position of the element 400, while cooling the tissue 408 during ablation.
  • the exterior surfaces of the bellows 412 are coated with an electrically conducting metal materi- al 420, like platinum.
  • Wires 423 (which pass through the flexible guide coil 312) electrically connect the metalized surfaces 420 to an external source of energy known to thermally destroy (i.e. ablate) body tissue.
  • an external source of energy known to thermally destroy (i.e. ablate) body tissue.
  • microwave energy and oth- er frequencies of electromagnetic radio frequency (RF) energy lying in the frequency range of from about 500 kHz to about 2.5 GHz are known to ablate body tissue.
  • the bellows 412 emit the ablation ener ⁇ gy conveyed by the wires 423.
  • the bellows 412 thereby serve, when used in association with a con ⁇ ventional external patch electrode or grounding plate (as before described) , as expandable elec ⁇ trodes to ablate tissue in the prostrate area for treating BPH.
  • the body 402 of the ablation element 400 houses an array of circumferentially spaced tubes 422. In use (see Fig. 22) the tubes 422 extend ra ⁇ dially outward from the body 402.
  • the tubes 422 are made of a conventional highly flexible, bioco patible material, such as a nickel-titanium alloy, stainless steel, and cobalt steel.
  • the tubes 422 are tapered to form sharpened terminal ends 424 that, in use, penetrate the surrounding tissue.
  • the tubes 422 are locat- ed between the expandable bellows 412.
  • the tubes 422 extend through the flexible guide tube 312, so that their proximal ends are accessible to the physician at the proximal end of the catheter tube 404.
  • the tubes 422 are carried in passages 426 within the body 402.
  • the passages 426 extend axial ⁇ ly along the body 402 and bend in a curved path to open radially at ports 428 in the side of the body 402.
  • the passages 426 (in concert with the flexible guide coil 312) guide movement of the flexible tubes 422 within the catheter tube 404 and body 402, under the control of the physician.
  • the tubes 422 flex within the passages 426, which direct the tubes 422 radially through the ports 428 and out the side of the body 402.
  • the tubes 422 can therefore be moved inside the body 402 (as Figs. 20 and 21 show) , retracted within the ports 428 away from tissue contact, dur ⁇ ing introduction of the element 400 into the pa ⁇ tient's body.
  • the tubes 422 can be selectively and individually deployed by the physician outside the ports 428 and into tissue along the side of the body 402 (as Figs. 22 to 24 show) .
  • the tubes 422 are hollow. They have open interior lumens 430 (see Fig. 22) that communicate with supply lines 432 that pass through the flexible guide coil 312 to the proximal end of the catheter tube 404 for connection to a source of saline (or another physiologic liquid) .
  • the tubes 422 dis ⁇ charge the liquid from the supply lines 432 into the surrounding tissue 408. By applying a vacuum through the supply lines 432, the tubes 422 also aspirate fluid from the surrounding tissue 408.
  • the tubes 422 thus serve to flush and remove debris from surrounding tissue 408 into which they penetrate.
  • the tissue penetrating regions 444 of the tubes 422 are conditioned to be elec ⁇ trically conducting.
  • the remainder 446 of the tubes 422 that extend through the guide coil 312 to the proximal end of the catheter tube 404 are either made of electrically non-conducting material or, if not, otherwise shielded with electrically non-con ⁇ ducting material.
  • the electrically conducting tube regions 444 are electrically coupled to supply lines 436 at the proximal end of the catheter tube 404.
  • the supply line 436 couple to a source of energy known to ablate tissue, as already described.
  • the electrically conducting tube regions 444 emit the ablation energy that the supply lines 436 conduct.
  • the electrically conducting tube regions 444 thus also serve as penetrating tissue ablation elements.
  • the tissue penetrating regions 444 of the tubes 422 are machined with helical patterns.
  • the supply lines 436 comprise coaxial ca ⁇ bles with proximal connectors for coupling the heli ⁇ cally machined regions 444 to a source of microwave energy.
  • the penetrating tube regions 444 therefore serve as microwave antennas that penetrate tissue and ablate the penetrated tis ⁇ sue for therapeutic benefits in treating BPH.
  • the ablation element 400 further includes various temperature sensing elements 440 to monitor temperature conditions surrounding the element 400.
  • An array of multiple temperature sensing elements 440 is located circumferentially about the distal tip 410 of the element.
  • One or more additional tem ⁇ perature sensors 440 are located on the body 402 in thermal contact with the fluid within the bellows 412.
  • a temperature sensor 440 (for example, a fiber optic temperature probe) is located within all or some of the lumens 430 in the tubes 422. Additional temperature sensors 440 are situated along the body 402.
  • the ablation element 400 also includes an ultrasound transponder 442 on its distal end 410.
  • the transponder 442 can be used in association with an ultrasound catheter (not shown) introduced into the patient's anus to locate the element 400 within the prostrate area of the body. Modification and variation can be made to the disclosed embodiments without department from the subject of the invention as defined in the fol ⁇ lowing claims.

Abstract

A medical probe device for contacting tissue within the body includes a catheter tube (6) having a control end and a probe end (16). The probe end (16) includes a housing (24) having a port (28). An element (40) is located within the housing and is movable between a first and second position. The element has a distal tip (34) adapted to penetrate tissue during movement. The element (40) comprises an electrode for emitting radio frequency energy into the tissue region.

Description

SYSTEMS AND METHODS FOR ABLATING BODY TISSUE Related Application
This application is a continuation-in-part of U.S. Patent Application Serial No. 08/100,086, filed July 30, 1993, entitled "Endocardial Infusion Catheter," naming as joint inventors Michael D. Lesh, Thomas F. Kordis, and Stuart D. Edwards. Background of the Invention Abnormal heart beats or cardiac arrhythmias can cause significant morbidity and mortality. These arrhythmias arise from a variety of causes, including atherosclerotic heart disease, ischemic heart disease, metabolic or hemodynamic derange- ments, rheumatic heart disease, cardiac valve dis¬ ease, certain pulmonary disorders and congenital etiologies. The normal heart rate is about 60 to 100 beats per minute. Arrhythmias refer to tachycardias at rates exceeding 100 beats per minute for a duration of at least 3 beats. Sometimes no treatment is required, such as in the tachycardia following a physiologic response to stress or exer¬ cise. However, in some cases, treatment is required to alleviate symptoms or to prolong the patient's life expectancy. 0367 PCMJS95/12257
- 2 -
A variety of treatment modalities exist, including electric direct current cardioversion, pharmacologic therapy with drugs such as quinidine, digitalis, and lidocaine, treatment of an underlying disorder such as a metabolic derangement, and abla¬ tion by either percutaneous (closed chest) or sur¬ gical (open chest) procedures. Treatment by abla¬ tion involves destruction of a portion of cardiac tissue which is functioning abnormally electrically. Normally the heat possesses an intrinsic pacemaker function in the sinoatrial (SA) node which is in the right atrium, adjacent to the entrance of the superior vena cava. The right atrium is one of four anatomic chambers of the heart. The other chambers are the right ventricle, the left atrium, and the left ventricle. The superior vena cava is a major source of venous return to the heart. The SA node is an area of specialized cardiac tissue called Purkinje cells and which measures roughly 1- 1/2 centimeters by about 2-1/2 millimeters. An electrical impulse normally exits from the SA node and travels across the atrium until it reaches the atrioventricular (AV) node. The AV node is located in the right atrium near the ventricle. Emerging from the AV node is a specialized bundle of cardiac muscle cells which originate at the AV node in the interatrial septum. This "bundle of His" passes through the atrioventricular junction and later divides into left and right branches which supply the left and right ventricles. The left and right bundles further give rise to branches which become the so-called distal His-Purkinje system, which extends throughout both ventricles.
Thus in a normal situation an impulse orig- inates intrinsically at the SA node, transmits through the atrium and is modified by the AV node. The AV node passes the modified impulse throughout the left and right ventricles via the His-Purkinje system to result in a coordinated heartbeat at a normal rate.
Many factors affect the heart rate in ad¬ dition to the intrinsic conduction system. For ex¬ ample, normally the heart rate will respond to phys¬ iologic parameters such as stress, exercise, oxygen tension and vagal influences. Additionally, there are multiple causes for an abnormal heartbeat such as an abnormal tachycardia. One group of such causes relates to abnormalities in the heart's conduction system. For example, ectopic or abnormally posi- tioned nodes may take over the normal function of a node such as the SA or AV node. Additionally, one of the normal nodes may be diseased such as from ischemic heart disease, coronary artery disease or congenital reasons. Similarly, a defect can exist in an important part of the conduction system such as the bundle of His or one of the bundle branches supplying the ventricles.
Treatment of abnormal tachycardias arising from ectopic foci or so-called ectopic pacemakers can include pharmacologic therapy or ablative ther¬ apy. The ablative therapy may be accomplished by percutaneous insertion of a catheter or by an open surgical cardiac procedure.
Cardiac arrhythmias may be abolished by ablating the tissue responsible for the genesis and perpetuation of the arrhythmias. Steerable ablation catheters using radio frequency (RF) energy are known. The RF energy can be directed to the area to be ablated and causes destruction of tissue by heat. In addition, direct infusion of ethanol has been performed during open heart surgery. Ethanol has also been infused into coronary arteries to ablate a focus such as a ventricular arrhythmia focus or the AV node. Unfortunately, this tends to result in a fairly large region of cardiac tissue death or myocardial infarction. With transarterial infusion there is difficulty in precisely controlling the location and extent of the ablation.
There are other conditions besides heart disease where tissue ablation by chemical or heat can achieve a therapeutic effect; for example, in the treatment of benign prostatic hypertrophy or hy- perplasia (BPH) . Summary of the Invention The present invention is directed to sys¬ tems and methods for ablating tissue in the body.
One aspect of the invention provides a med¬ ical probe device for contacting tissue within the body. The device comprises a catheter tube having a control end and a probe end. The probe end in¬ cludes a housing having a port. An element is lo¬ cated within the housing. The element is movable between a first position confined within the housing and a second position extending through the port outside the housing. The element has a distal tip adapted to penetrate a tissue region during movement between the first and second position. The element comprises either an electrode for emitting electro¬ magnetic radio frequency energy into the tissue re- gion, or a cannula with an interior lumen for con¬ veying fluid to and from the tissue region, or a sensor for sensing temperature conditions in the tissue region.
In one embodiment, the element has a threaded exterior with a distal tip adapted to pene- trate a tissue region in response to rotation of the element during movement between the first and second position.
Another aspect of the invention provides a method for ablating tissue within the body. The method introduces a catheter tube having a control end and a probe end in the body. The probe end in¬ cludes a housing and an element within the housing movable between a first position confined within the housing and a second position extending outside the housing. The element has a distal tip adapted to penetrate a tissue region during movement between the first and second position. During introduction into the body, the element is located in the first position within the housing.
The method places the probe end in contact with a tissue region and moves the element from the first position to the second position to penetrate the contacted tissue region. The method ablates the tissue region, while the element penetrates it, by either emitting electromagnetic radio frequency en¬ ergy through the element into the tissue region or conveying ablation fluid through a lumen in the ele¬ ment for discharge into the tissue region. For use in ablation of cardiac tissue, the catheters in one preferred embodiment of the inven¬ tion have an elongated flexible body and a tissue ablation assembly having a tissue ablation tip at the distal end of the body. The distal end of the catheter is introduced into a cardiac chamber (or other body region) including the tissue to be ab¬ lated. The catheter may be equipped for standard arrhythmia mapping, for example multiple electrodes may be present on the outside of the catheter for recording endocardial electrograms. Alternatively, the catheter may include a visualization assembly at the distal end of the body. The visualization as¬ sembly is used to position the tip of the catheter adjacent the tissue to be ablated. Catheters com- prising visualization and ablation means are de¬ scribed in copending application Serial No. 08/099,995, Filed July 30, 1993, entitled "Cardiac Imaging and Ablation Catheter," which is incorpo¬ rated herein by reference. In one embodiment, the tissue ablation as¬ sembly comprises a hollow infusion needle which can be extended or withdrawn from the distal end of the catheter. The hollow infusion needles of the inven¬ tion have a securing element configured to engage tissue when the needle is at least partially insert¬ ed into the tissue to stop recoil and help prevent inadvertent removal of the needle from the tissue. The securing element can be configured into the form of corkscrew or threads surrounding a straight nee- die. Alternatively, the securing element can be configured as a plurality of pre-curved needles, which curve towards or away from the longitudinal axis of the catheter. The pre-curved needles can also be used to deliver ablation compounds if de- sired. Other structures, such as barbs, could also be used as the securing element. The hollow infu¬ sion needle is preferably a corkscrew-shaped needle, with a tight curl. The distance between turns is preferably about 0.5 mm or less. Such a needle al- low the practitioner to inject through layers by slowly extending the needle, injecting, extending farther and injecting again.
When used to ablate tissue the catheter can be used with a conventional ablation compound such as alcohol (e.g., ethanol) , collagen, phenol, carbon dioxide and the like. The solution may comprise various components for other purposes as well. For instance, an echocontrast agent for echo imaging may be included. Collagen can be bound to an iodinated molecule to make it radiodense. Alternatively, when used for gene therapy protocols, the catheters of the invention can be used to introduce desired poly- nucleotides to the target tissue.
When performing a percutaneous or closed chest cardiac ablation procedure using the catheters of the invention, fluoroscopy can be used to visu¬ alize the chambers of the heart. Fluoroscopy uses roentgen rays (X-rays) and includes use of a spe¬ cialized screen which projects the shadows of the X- rays passing through the heart. Injectable contrast agents to enhance the fluoroscopic picture are well known in the art and are not described in detail here.
Typically, the catheter is placed in an artery or a vein of the patient depending on whether the left (ventricle and/or atrium) or right (ventri¬ cle and/or atrium) side of the heart is to be ex¬ plored and portions thereof ablated. Frequently an artery or vein in the groin such as one of the femo- ral vessels is selected for catheterization. The catheter is passed via the blood vessel to the vena cava or aorta, also depending on whether the right or left side of the heart is to be catheterized, and from there into the appropriate atrium and/or ven- tricle.
The catheter is generally steerable and it is positioned against an endocardial region of in¬ terest. As mentioned above, the catheter typically includes a means for sensing the electrical impulses originating in the heart. Thus, the electrode cath- eter can provide a number of electrocardiogram read¬ ings from different areas of the internal aspects of the heart chambers. These various readings are cor¬ related to provide an electrophysiologic map of the heart including notation of normal or abnormal fea¬ tures of the heart's conduction system. Once the electrophysiologic map is produced, an area may be selected for ablation.
Typically, before final ablation, the sus- pect area is temporarily suppressed or deadened with a substance such as lidocaine or iced saline solu¬ tion. Subsequently the area is remapped and heart reevaluated to determine if the temporary measure has provided some electrophysiologic improvement. If improvement has occurred, then the clinician ma proceed with permanent ablation typically using eth- anol.
In one aspect, the present invention pro¬ vides the novel combination of tissue ablation and tissue imaging in a single catheter to permit abla¬ tion of tissue to be properly accomplished by the correct selection of the ablation site and monitor¬ ing and controlling the ablation of the tissue being destroyed. The invention is preferably used with imaging ultrasonic transceivers in an ablation cath¬ eter to provide real time assessment of lesion vol¬ ume and to monitor the tissue being ablated. Alter¬ natively, one or more A-mode ultrasonic crystals can be used. As used herein, a visualization means of the invention may be either an imaging or an A-mode ultrasonic device. One or more transponder can also be used to assist in localizing the catheter tip.
For use in treating BPH, the catheters in one preferred embodiment of the invention have abla- tion elements that move outward to penetrate tissue from the side of the probe. The ablation elements either emit electromagnetic radio frequency energy to heat and thermally destroy the penetrated tissue or convey an ablation fluid to chemically destroy the penetrated tissue.
Other features and advantages of the inven¬ tion will appear from the following description in which the preferred embodiments have been set forth in detail in conjunction with the accompanying draw- ings.
Brief Description of the Drawings
Fig. 1 is an overall view of a catheter made according to the invention;
Fig. 2 is an enlarged, simplified cross- sectional view of the distal end of the flexible body of Fig. 1;
Fig. 3 is an enlarged, schematic cross-sec¬ tional view of the distal end of the flexible body of Fig. 1 illustrating the general locations of the tip electrode, ultrasonic transducer, and ring elec¬ trodes;
Fig. 4 is an overall view of an alternative catheter made according to the invention;
Fig. 5 is an enlarged, simplified cross- sectional view of the tip and the catheter of Fig. 4, shown with a hollow needle retracted;
Fig. 6 is an external view of the tip of Fig. 5 with the hollow needle extended;
Fig. 7 is an enlarged view of the needle driver and infusion port mounted to the handle of Fig. 4
Fig. 8 is an enlarged, simplified cross- sectional view of the tip of a catheter with a hol¬ low needle retracted; Fig. 9 illustrates the handle assembly of a catheter of the invention;
Fig. 10A is an enlarged, simplified cross- sectional view of the tip of a catheter with the anchoring needles and hollow needle in the extended position;
Fig. 11A is an enlarged, simplified cross- sectional view of the tip of a catheter with the anchoring/infusion needles in the extended position;
Fig. 11B is an end view of catheter tip in Fig. 11A;
Fig. 12 is an end view of a catheter tip with 10 anchoring/infusion needles;
Fig. 13A is an enlarged, simplified cross- sectional view of the tip of a catheter showing the triggering mechanism with the anchoring/infusion needles in the retracted position;
Fig. 13B is an enlarged, simplified cross- sectional view of the tip of a catheter showing the triggering mechanism with the anchoring/infusion needles in the extended position;
Fig. 14 illustrates the handle assembly of a catheter of the invention showing the trigger for releasing and retracting the anchoring needles;
Fig. 15 is a catheter carrying at its dis- tal end a multi-function probe that embodies the features of the invention;
Fig. 16 is an enlarged section view of the multi-function probe, which the catheter shown in
Fig. 15 carries at its distal end, with the associ- ated screw ablation element located in its retracted position;
Fig. 17 is an enlarged view of the multi¬ function probe with the associated screw ablation element located in its extended position; Fig. 18 is a perspective view of the screw ablation element shown in Figs. 16 and 17 deployed in its extended position in tissue;
Figs. 19A, B, C, and D are diagrammatic views showing the use of the multi-function probe shown in Fig. 15 in ablating tissue in the left ven¬ tricle of the heart;
Fig. 20 is an ablation element suited for the treatment of benign prostatic hypertrophy, with its associated expandable ablation electrodes col- lapsed and its associated penetrating ablation elec¬ trodes retracted;
Fig. 21 is a top view of the ablation ele¬ ment shown in Fig. 20;
Fig. 22 is the ablation element shown in Fig. 20, with its associated expandable ablation electrodes inflated and its associated penetrating ablation electrodes extended and penetrating tissue; Fig. 23 is a top view of the ablation ele¬ ment shown in Fig. 22; and Fig. 24 is a diagrammatic view of the abla¬ tion element when deployed for use in the prostrate region of the body. Description of the Preferred f-nfaa-iiment
Fig. 1 illustrates a catheter 2 having a handle 4 from which a flexible body 6 extends. Flexible body 6 extends from one end 8 of handle 4 while ultrasonic cable 10 and a combination elec¬ trode/thermistor cable 12 extend from the other end 14 of handle 4. Distal end 16 of flexible body 6 is steerable, as suggested by the dashed lines 18 in Fig. 1, in a conventional manner using a steering lever 20 mounted to handle 4. Lever 20 which con¬ trols one or more steering cables 22, see Fig. 2, as is conventional. Distal end 16 has an RF transmit- ting tip 24 secured thereto. Transmitting tip 24 is connected to an appropriate RF energy source, not shown, through lead 26 which extends along flexible body 6, through handle 4 and through combined cable 12. Tip 24 has a pair of axially extending bores 28, 30 formed from its distal end 32. Bore 28 is used to house an ultrasonic transducer 34 while bore 30 is used to house a thermistor 36. Transduc¬ er 34 is surrounded by a thermal insulating sleeve 38, typically made of insulating material such as polyimide. The base 40 of transducer 34 has a lead 41 extending from transducer 34, along flexible body 6, through handle 4 and through ultrasonic cable 10. The ultrasonic transducer comprises a piezoelectric crystal capable of operating at a standard frequen¬ cy* typically from about 5 to about 5 MHz. The crystal is formed from standard materials such as barium titanate, cinnabar, or zirconate-titanate. The transducer 34 generates an ultrasonic pulse in response to electrical impulses delivered through lead 41. Ultrasonic echoes are then received by the ultrasonic transducer 34 which generates electrical signals which are delivered to the receiving unit (not shown) . The transducer is connected to conven- tional transmitting and receiving units which in¬ clude the circuitry necessary for interpreting the ultrasonic information and displaying the informa¬ tion on a visual display. Signal processing may take advantage of change in tissue density or tex- ture as correlated with lesion depth. The ultrason¬ ic signal can be visualized on a two dimensional echocardiograph or using non-imaging A-mode.
Base 40 of transducer 34 is sealed with a UN potting adhesive 42, such as Tough Medical Bonder made by Loctite, to provide both thermal and elec- trical insulation. The catheter also comprises an ultrasonic transponder 44, shown schematically in Fig. 3, spaced about 2.5 mm from RF transmitting tip 24 at the distal end 16 of body 6. Transponder 44 is used to help in localization of the catheter tip as is known in the art and described in Langberg et al., JACC 12:218-223 (1988). In alternate embodi¬ ments, multiple transponders can be used to help with assessing catheter tip orientation as well. In the embodiment of Figs. 1-3, the abla¬ tion apparatus exemplified by the use of RF trans¬ mitting tip 24. In addition to tip electrode 24, catheter 2 also includes three ring electrodes 46, 47, 48 positioned in a proximal direction, that is towards handle 4 relative to tip electrode 24 and transducer 44. Electrodes 46-48 (spaced 2.5 mm apart) are used to record electrical signals pro¬ duced by the heart (electrocardiograms) for endocar¬ dial mapping using a multichannel EKG machine as is known in the art. Thermistor 36 is coupled to com¬ bination cable 12 through a lead 50 extending from thermistor 36, to flexible body 6, through handle 4 and into combination cable 12. Thermistor 36 is used to provide information about the temperature of the tissue at the distal end 32 of tip 24.
Separately, the above-discussed apparatus used to create ultrasonic visualization of the tis¬ sue to be ablated is generally conventional. As discussed above, the ultrasonic visualization means may be used for either imaging or A-mode. One such ultrasonic imaging system is sold by Cardiovascular Imaging Systems of Sunnyvale, California. Similar¬ ly, the RF ablation system, used to ablate the tis¬ sue, is also generally conventional, such as is sold, for example, by EP Technologies, Inc. of Sunnyvale, California. What is novel is incorporat¬ ing both the imaging and ablation structure into a single catheter which permits real time visualiza¬ tion and accurate positioning of the RF transmitter tip 24 with the precise location to be ablated. The amount or volume of tissue ablated can thus be con¬ stantly monitored during the procedure so that nei¬ ther too little or too much tissue is ablated for maximum control and effectiveness. The use of tem- perature monitoring using thermistor 36 is also gen¬ erally conventional as well, but not in conjunction with an ultrasonic imaging assembly. Instead of using RF energy to ablate the tissue, microwave ra¬ diation, laser energy, cryoblation or endocardial injection/infusion, for example, can be used in con¬ junction with ultrasonic transducer 34.
The use of catheter 2 proceeds generally as follows. Distal end 16 of body 6 is directed to the appropriate site using conventional techniques and steering lever 20. Visualization of the tissue to be ablated and localization of the tip 24 is provid¬ ed by ultrasonic transducer 34, ultrasonic tran¬ sponder 44, and associated leads and cables coupled to a conventional ultrasonic imaging console, not shown. When tip 24 is at the site of the tissue to be ablated, RF generator, not shown, coupled to combination cable 12, is activated to produce RF radiation at tip 24 to ablate the tissue. The ab¬ lation is monitored by ultrasonic transducer 34 as well as thermistor 36 to help ensure that the proper volume of tissue is ablated. When the proper volume of tissue is ablated, body 6 is removed from the patient. Instead of the use of catheter 2 including an RF transmitter tip 24, the catheter could use an ablation fluid infusion tip similar to that shown in Figs. 4-7. Also, preparatory to the ablation se¬ quence, the suspect area can be temporarily sup¬ pressed to deadened using catheter 60 using lido¬ caine or iced saline solution, as discussed in the Background section above.
Referring the reader now to Figs. 4-7, a catheter 60 is shown. Catheter 60 includes a handle 62 from which a flexible body 64 extends. Handle 62 includes a steering lever 65 and combination infu- sion port 66 and needle driver 68 at the distal end 70 of handle 62. A pair of cables 72 extend from the proximal end 74 of handle 62. A pair of cables 72 extend from the proximal end 74 of handle 62. The distal end 76 of flexible body 64 has a tip as- sembly 78 mounted thereto. Tip assembly 78 includes mapping electrodes 80 connected to wires 82 which extend down flexible body 64, through handle 62 and to cables 72. Mapping electrodes 80 provide the user with a nonvisual indication of where tip assem- bly is by monitoring the electro-activity of the heart muscle, as is conventional. Electrodes 80 are electrically isolated from the remainder of tip as¬ sembly 78 by an insulating sleeve 84.
A hollow needle 86 is slidably mounted within a second insulating sleeve 88 housed within insulating sleeve 84. The needle may be formed from standard metal alloys such as titanium alloy, stain¬ less steel, and cobalt steel. The needle 86 is a corkscrew-shaped needle used to inject ablating liq- uid into tissue and secure the needle to the tissue. Other designs of hollow needles, including the use of barbs on a straight or curved needle, can be used as well. While hollow needle 86 is shown used with a generally conventional mapping electrode type of catheter, it could be used with an ultrasonic visu- alization assembly as shown in Figs. 1-3, as well as other types of visualization assemblies.
A central bore 90 of hollow needle 86 is coupled to infusion port 66 by an infusion fluid tube 92 which extends along flexible body 674, through needle driver 68 and to infusion port 66. Threaded needle driver 68 is connected to a tip ex¬ tension 94 so that rotating needle driver 68 causes tip extension 94 to rotate about the axis 95 of nee- die 86 and to move axially within flexible body 64. This causes hollow needle 86 to rotate about axis 95 and to move axially within sleeve 88 from the re¬ tracted position of Fig. 5 to the extended position of Fig. 6. Rotating needle driver 68 also rotates hol¬ low needle 86 so that it bores into the tissue to be ablated. When properly in position, an appropriate liquid, such as ethanol, can be infused into the tissue to be ablated through infusion port 66, in- fusion fluid tube 92, hollow needle 86, and into the tissue. Since the tip 100 of hollow needle 86 is buried within the tissue to be ablated, the operator is assured that the ablation liquid is delivered to the proper place while minimizing ablation of sur- rounding tissue.
The needle is typically used to inject an ablation liquid endocardially to produce a more cir¬ cumscribed lesion than that possible using prior art infusion techniques. The needle is designed such that it can be imbedded in and secured to the tissue to be treated.
Although ablation of cardiac tissue is a preferred use of the catheters of the invention, they can be used to inject desired compositions for a wide variety of uses. Virtually any therapeutic compound can be delivered intracardially using the catheters of the invention. For instance, the cath¬ eters can be used to deliver compositions comprising modified genes to cardiac or other tissue for use in gene therapy protocols. Methods for introducing a variety of desired polynucleotides to target cells using, for example, retroviral vectors are well known. Examples of sequences that may be introduced include antisense polynucleotides to control expres- sion of target endogenous genes. In addition, genes encoding toxins can be targeted for delivery to can¬ cer cells in tumors. In other embodiments, homolo¬ gous targeting constructs can be used to replace an endogenous target gene. Methods and materials for preparing such constructs are known by those of skill in the art and are described in various refer¬ ences. See, e.g., Capecchi, Science 244:1288 (1989) .
Other uses include intramyocardial delivery of isolated cells or cell substitutes. These ap¬ proaches typically involve placement of the desired cells on or within matrices or membranes which pre¬ vent the host immune system from attacking the cells but allow nutrients and waste to pass to and from the cells (see, Langer et al., Science 260:920-925 (1993)). For instance, sinus node cells can be im¬ planted in a desired location to treat disorders in impulse formation and/or transmission that lead to bradycardia. Turning now to Fig. 8, the distal end 102 of a catheter of the present invention is shown. The hollow corkscrew infusion needle 104 is movably positioned within flexible distal tube 106. The flexible tube 106 allows movement of the distal end 102 in response to the steering mechanism 112. The steering mechanism 112 is conventional and functions as is known in the art. The distal end 102 also comprises mapping electrodes 108 which monitor elec¬ tro activity of the heart muscle as described above. The mapping electrodes are connected through signal wires 111 to standard multichannel EKG machine as is known in the art.
The braided torque tube 114 is connected to the inside diameter of the infusion needle 104 and provides means for rotating the infusion needle 104 about the longitudinal axis 105 of the catheter and moving the needle 104 axially within the distal tube 106. The braided torque tube 114 consists of stan¬ dard flexible tubing overlapped with a wire braid which stiffens the tube and allows torquing of the tube to rotate the needle 104.
Fig. 9 shows the handle assembly 115 of a catheter of the present invention. The braided tube 114 is connected to an infusion needle ad- vance/retract knob 116 by which the user controls axial movement of the infusion needle 104. A female luer lock infusion port is positioned on the ad¬ vance/retract knob 116. A standard strain relief means 118 prevents kinking of the flexible tube 119. Also provided is a handle 120 secured to the cathe¬ ter through front handle support 122 and rear handle support 124. The handle assembly 115 is attached to a standard steering/mapping catheter handle 130 as is conventional and signal wires 132 are connected to the appropriate receiving units.
Figs. 10A through 10C show the distal end 134 of a catheter comprising an infusion needle 136 connected to a braided torque tube 138 as described above. The distal tube 142 also comprises an elas- to eric seal 152 made from standard materials well known to those of skill in the art. The elastomeric seal 152 provides a seal for the distal tube 142 and prevents blood from flowing into the lumen of the catheter. Typically, the infusion needle 136 is coated with a compound such as mold release, to fa¬ cilitate movement of the needle through the elasto¬ meric seal 152.
Also included in this embodiment is a set of spring loaded pre-curved anchoring needles 144 positioned near the outer edge of the distal tube 142. The anchoring needles are attached to a shut¬ tle 150 and compression spring 146 which are trig¬ gered through pull wires 148 through a trigger de¬ vice on the handle. The function of the trigger device is shown more fully in Figs 13A, 13B and 14.
Fig. 10B shows the extended anchoring nee¬ dles 144 after the triggering device has released the shuttle 150 and compression spring 146. This mechanism permits the distal end of the catheter to be attached in an almost instantaneous fashion and eliminates the effects of cardiac motion on the at¬ tachment procedure. Fig. 10C is an end view of the distal end 134 showing the position of the pre- curved anchoring needles 144 after release. In the embodiment shown here, the anchoring needles 144 are curved towards the longitudinal axis of the cathe¬ ter. The anchoring needles 114, however, can be curved towards or away from the longitudinal axis. Figs. 11A and 11B show a further embodiment of the catheter comprising anchoring needles 162 which are used for infusion as well as anchoring. In this embodiment, the needles 162 are connected to infusion channel 160 through which the ablation liq¬ uid or other compound is delivered to the infusion needles 162. The infusion needles 162 are shown in the extended position after the shuttle 166 and com¬ pression spring 164 have moved the needles 162 axi¬ ally through the distal tube 156. As with other embodiments, map electrodes 152 can be used to cre- ate an electro physiological map of the tissue. Braided tube 158 is used to anchor the compression spring 164. The infusion needles are curved outward as well as inward in this embodiment (Figure 11B) . Fig. 12 is an end view of the distal end 168 of a catheter of the invention showing the ar¬ rangement of infusion needles 170 in which five nee¬ dles project away from the longitudinal axis and five project toward the axis.
Figs. 13A and 13B illustrate the trigger assembly by which the pre-curved needles 200 ar re¬ leased from the distal end 202 of the catheters of the present invention. Fig. 13A shows the pre- curved needles 200 in the retracted position within the flexible distal tube 204. The pre-curved nee- dies 200 are attached to the shuttle 206 which is held in place by three trigger tabs 208, two of which are illustrated in Fig. 13A. The trigger tabs 208 are permanently fixed to the front stop 210 and pre-loaded against the inner diameter 212 of the distal tube 204.
As in the other embodiments disclosed above, the pre-curved needles 200 are fluidly con¬ nected to infusion channel 214, which enters the flexible distal tube distal 204, through braided tube 211. Map electrodes 216 are used to create an electro physiological map of the heart as described.
Fig. 13B shows the pre-curved needles 200 in the extended position after the trigger tabs 208 have been pulled towards the longitude axis of the catheter by the trigger pull wires 220. Once the trigger tabs 208 have been pulled towards the lon¬ gitude axis, the shuttle 206 is released and the compression spring 222 drives the shuttle 206 and needles 200 rapidly towards the distal tip of the catheter. The inertia of the catheter body prevents the tip from withdrawing and needles 200 ar subse¬ quently driven into the target tissue. Fig. 13B also shows the position of the trigger tabs 208 on the inner diameter of the shuttle 206 after the shuttle 206 has moved forward. After use the shut¬ tle pull wires 218 are activated to pull the pre- curved needles 200 to the retracted position.
Fig. 1 A shows the handle assembly 230 com¬ prising a handle body 232 from which this position and ablation tip steering lever 234. The handle body 232 comprises a needle trigger 236 which is shown in both the cocked and fired (dashed lines) positions. The distal end of the trigger wires 238 are attached between the distal end 240 and the piv- ot point 242 to insure the wires 238 are pulled when the lever is pulled. The retractor 244 is shown in the cocked and fired (dashed lines) positions, as well. The pull wires 244 are attached between the pivot point 246 and the distal end of the retractor 248 as for the trigger. The handle assembly in¬ cludes a lead 250 which allows for connection to appropriate ablation compound as described above.
Fig. 15 shows a catheter 300 having at its distal end a multi-function probe assembly 302 capa- ble of sensing physiological events in endocardial and myocardial tissue, thermally stunning endocardi¬ al and myocardial tissue, and ablating myocardial tissue. The catheter 300 includes a conventional flexible guide coil 312 within a catheter tube 304 made of an electrically non-conducting material, like polyurethane (see Fig. 16) . The proximal end of the catheter tube 304 carries a handle 306. The handle 306 allows the physician to remotely control the probe assembly 302 in the body. Preferably, the distal end of the catheter tube 304 is steerable by conventional means, thereby also steering the probe assembly 302. For this pur¬ pose, the handle 306 carries a steering lever 308 attached by steering wires (not shown) to steering springs 310 in the distal end of the catheter tube 304 (see Fig. 16) .
As Figs. 16 and 17 show, the probe assembly 302 includes electrodes 314 and 316 that sense phys¬ iological events in heart tissue. In the illustrat- ed embodiment, the electrodes 314 senses monophasic action potentials (MAP) in conventional fashion. The electrode 316 comprises the reference electrode for the MAP electrode 314.
The probe assembly 302 houses an ablation electrode 318. The ablation electrode 318 is made from a biocompatible material known to conduct elec¬ tricity, like platinum or stainless steel. The electrode 318 is formed in the shape of a hollow screw. The electrode 318 will thus be called a "screw electrode." The screw electrode 318 includes a tapered or pointed exterior surface 320, which is sharpened for penetration of tissue. The surface 320 is also threaded, like, for example, a wood screw, for advancement into tissue when rotated. A sleeve 322 guides and directs movement of the screw electrode 318 along an axial path within the probe assembly 302. The sleeve 322 is made of an electrically non-conductive material (like poly¬ urethane) to thereby electrically insulate the screw electrode 318 from the MAP electrodes 314. The ex- terior of the probe assembly 302, except for the MAP electrodes 314 and reference electrode 316, is fur¬ ther enclosed by a sleeve 323 of electrically non¬ conducting material, which abuts against the cathe- ter tube 304.
The base 324 of the screw electrode 318 is attached to a tip extending shaft 326. The shaft 326 passes through the guide coil 312 to a screw extend¬ er 328 on the handle 306 (see Fig.15). Rotation of the screw extender 328 by the physician is translat¬ ed by the shaft 326 into rotation and axial advance¬ ment of the screw electrode 318, which the sleeve 322 guides to move the screw electrode 318 between a retracted position within the probe assembly 302 (as Fig. 16 shows) and an extended position outside the probe assembly 302 (as Fig. 17 shows) .
Insulated wires 330, 332, and 334 pass through the guide coil 312 for electrical connection to components of the probe assembly 302. The wires 330 and 332 are electrically coupled to the MAP electrodes 314 and the MAP reference electrode 316. The wire 334 is electrically coupled to the screw electrode 318.
The proximal ends of the wires 330, 332, and 334 pass into the handle 306. The wires 330, 332, and 334 are electrically coupled within the handle 306 to external connectors 336. The connec¬ tors 336 plug into a source of energy known to ther¬ mally destroy (i.e., ablate) body tissue. For exam- pie, microwave energy and other frequencies of elec¬ tromagnetic radio frequency (RF) energy (lying in the frequency range of from about 500 kHz to about 2.5 GHz) are known to ablate body tissue. The wire 334 conveys the selected energy to the screw elec- trode 318 for transmission through tissue, when used in association with a conventional external patch electrode (called an "indifferent" electrode) at¬ tached to the patient's skin or to a grounding plate that the patient lies upon. The connectors 336 also plug into an external conventional device for pro¬ cessing the MAP signals, which are conveyed by the wires 330 and 332.
The screw electrode 318 also includes an interior passage or lumen 338 which communicates with an injection fluid tube 340. The injection fluid tube 340 extends through the guide coil 312 to an injection site 342 carried on the handle 306 (see Fig. 15) . The interior passage 338 communicates with outlets 344 in the exterior surface 320 of the screw electrode 318 for discharging fluid carried by the injection fluid tube 340.
In use, the physician deploys the distal probe assembly 302 into the contact with tissue 346, which Fig. 19A diagrammatically shows to be within the left ventricle of the heart. With firm contact established, the physician uses the MAP electrodes 314 to measure MAP signals to locate an early acti¬ vation site (EAS) using conventional techniques.
Once an EAS is located, the physician ro- tates the screw extender 328 to advance the screw electrode 318 into heart tissue where the EAS is found (as Figs. 18 and 19B show) . The physician injects very cold (iced) saline with a syringe 348 (see Fig. 1) through the injection site 342. The outlets 344 on the screw electrode 318 discharge the cold saline into the surrounding tissue 346 (shown by arrows in Figs. 18 and 19B) . Alternatively, the physician can introduce carbon dioxide through the injection site 342, which results in cooling (through Joule-Thompson expansion) at the outlets 344 of the screw electrode 318.
The cold temperature temporarily stuns the surrounding tissue 346. The stunning electrically isolates the tissue from the surrounding myocardium, during which time the tissue physiology emulates dead tissue. Confirming that a given tacharrhymia cannot be induced when tissue 346 is stunned vali¬ dates that a correct site for ablation has been lo¬ cated. Next, without repositioning the probe as¬ sembly 302, and with the screw electrode 318 left imbedded in the tissue 346, the physician applies ablation energy to the screw electrode 318 for transmission into surrounding tissue (as the wave lines in Fig. 19C show) . Since the screw electrode 318 is imbedded in tissue 346, the ablation energy reaches myocardial tissue significantly below the endocardium, deeper than a surface ablation elec¬ trode could reach. As an alternative to RF ablation, the phy¬ sician can inject alcohol through the injection site 342, which the outlets 344 on the screw electrode 318 discharge into the surrounding tissue area. The alcohol ablates the tissue by chemical means rather than by heating, as RF energy does.
The physician can validate the elimination of arrhythmia following ablation by reviewing endo¬ cardial electrograms. Once validation occurs, the physician rotates the screw extender 328 to withdraw the screw electrode 318 into its retracted position. The physician can withdraw the assembly 302 from the heart, or repeat the above steps, as necessary, to locate and eliminate multiple arrhythmia sources.
Figs. 20 to 24 show an ablation element or probe 400 suited for the treatment of benign pros- tatic hypertrophy or hyperplasia (BPH) . The ablation element 400 includes a body 402 attachable to the end of a conventional catheter tube 404 for inser¬ tion through the urethra (see Fig. 24) into contact with prostrate tissue 408. The catheter tube 404 itself can be like that shown in Figs. 15 and 16, with a flexible guide coil 312 running through it and a handle 306 at its proximal end. The body 402 of the ablation element 400 is made of an electri- cally non-conducting material conventionally used for medical use catheters, for example polyurethane. The diameter of the body 402 is about 20 Fr. , or larger.
The element 400 includes near its distal end 410 one or more expandable bellows 412. The bel¬ lows 412 are made of a biocompatible elastomeric material, like silicone rubber. The bellows 412 are attached by upper and lower fluid-tight lock bands 414 circumferentially about the body 402. Fluid lines 416 extend within the body 402 and communicate with each bellows 412. The fluid lines 416 pass through the flexible guide coil 312 and exit the proximal end of the catheter tube 404 for attachment to an external source of saline solu- tion (or another physiologically compatible liquid) . The fluid lines 416 convey the solution from the external source into the bellows 412. As Fig. 22 shows, the fluid expands the bellows 412, urging them into contact with tissue 408. The fluid-filled bellows 412 stabilize the position of the element 400, while cooling the tissue 408 during ablation.
In the illustrated and preferred embodi¬ ment, the exterior surfaces of the bellows 412 are coated with an electrically conducting metal materi- al 420, like platinum. Wires 423 (which pass through the flexible guide coil 312) electrically connect the metalized surfaces 420 to an external source of energy known to thermally destroy (i.e. ablate) body tissue. As before stated, microwave energy and oth- er frequencies of electromagnetic radio frequency (RF) energy lying in the frequency range of from about 500 kHz to about 2.5 GHz are known to ablate body tissue. The bellows 412 emit the ablation ener¬ gy conveyed by the wires 423. The bellows 412 thereby serve, when used in association with a con¬ ventional external patch electrode or grounding plate (as before described) , as expandable elec¬ trodes to ablate tissue in the prostrate area for treating BPH. The body 402 of the ablation element 400 houses an array of circumferentially spaced tubes 422. In use (see Fig. 22) the tubes 422 extend ra¬ dially outward from the body 402. The tubes 422 are made of a conventional highly flexible, bioco patible material, such as a nickel-titanium alloy, stainless steel, and cobalt steel. The tubes 422 are tapered to form sharpened terminal ends 424 that, in use, penetrate the surrounding tissue. In the illustrated embodiment, the tubes 422 are locat- ed between the expandable bellows 412. The tubes 422 extend through the flexible guide tube 312, so that their proximal ends are accessible to the physician at the proximal end of the catheter tube 404.
The tubes 422 are carried in passages 426 within the body 402. The passages 426 extend axial¬ ly along the body 402 and bend in a curved path to open radially at ports 428 in the side of the body 402. The passages 426 (in concert with the flexible guide coil 312) guide movement of the flexible tubes 422 within the catheter tube 404 and body 402, under the control of the physician. The tubes 422 flex within the passages 426, which direct the tubes 422 radially through the ports 428 and out the side of the body 402. The tubes 422 can therefore be moved inside the body 402 (as Figs. 20 and 21 show) , retracted within the ports 428 away from tissue contact, dur¬ ing introduction of the element 400 into the pa¬ tient's body. The tubes 422 can be selectively and individually deployed by the physician outside the ports 428 and into tissue along the side of the body 402 (as Figs. 22 to 24 show) .
The tubes 422 are hollow. They have open interior lumens 430 (see Fig. 22) that communicate with supply lines 432 that pass through the flexible guide coil 312 to the proximal end of the catheter tube 404 for connection to a source of saline (or another physiologic liquid) . The tubes 422 dis¬ charge the liquid from the supply lines 432 into the surrounding tissue 408. By applying a vacuum through the supply lines 432, the tubes 422 also aspirate fluid from the surrounding tissue 408. The tubes 422 thus serve to flush and remove debris from surrounding tissue 408 into which they penetrate. The tissue penetrating regions 444 of the tubes 422 (see Fig. 22) are conditioned to be elec¬ trically conducting. The remainder 446 of the tubes 422 that extend through the guide coil 312 to the proximal end of the catheter tube 404 are either made of electrically non-conducting material or, if not, otherwise shielded with electrically non-con¬ ducting material. The electrically conducting tube regions 444 are electrically coupled to supply lines 436 at the proximal end of the catheter tube 404. The supply line 436 couple to a source of energy known to ablate tissue, as already described. The electrically conducting tube regions 444 emit the ablation energy that the supply lines 436 conduct. The electrically conducting tube regions 444 thus also serve as penetrating tissue ablation elements.
In the illustrated embodiment, the tissue penetrating regions 444 of the tubes 422 (which, in the illustrated embodiment, are made from electri¬ cally conducting material) are machined with helical patterns. The supply lines 436 comprise coaxial ca¬ bles with proximal connectors for coupling the heli¬ cally machined regions 444 to a source of microwave energy. In this embodiment, the penetrating tube regions 444 therefore serve as microwave antennas that penetrate tissue and ablate the penetrated tis¬ sue for therapeutic benefits in treating BPH.
The ablation element 400 further includes various temperature sensing elements 440 to monitor temperature conditions surrounding the element 400. An array of multiple temperature sensing elements 440 is located circumferentially about the distal tip 410 of the element. One or more additional tem¬ perature sensors 440 are located on the body 402 in thermal contact with the fluid within the bellows 412. A temperature sensor 440 (for example, a fiber optic temperature probe) is located within all or some of the lumens 430 in the tubes 422. Additional temperature sensors 440 are situated along the body 402. The ablation element 400 also includes an ultrasound transponder 442 on its distal end 410. The transponder 442 can be used in association with an ultrasound catheter (not shown) introduced into the patient's anus to locate the element 400 within the prostrate area of the body. Modification and variation can be made to the disclosed embodiments without department from the subject of the invention as defined in the fol¬ lowing claims.

Claims

We claim:
1. A medical probe device for contacting tissue within the body, the device comprising a catheter tube having a control end and a probe end, the probe end including a housing having a port, an element within the housing movable between a first position confined within the housing and a second position extending through the port outside the housing, the element having a distal tip adapted to penetrate a tissue region during movement between the first and second position, the element compris¬ ing an electrode for emitting electromagnetic radio frequency energy into the tissue region, or cannula with an interior lumen for conveying fluid to and from the tissue region, or a sensor for sensing tem- perature conditions in the tissue region.
2. A medical probe device for contacting tissue within the body, the device comprising a catheter tube having a control end and a probe end, the probe end including a housing with a side wall and a port in the side wall, an element within the housing movable between a first position confined within the housing and a second position extending through the port outside the housing, the element having a distal tip adapted to penetrate a tissue region during movement between the first and second position, the element comprising an electrode for emitting electromagnetic radio frequency energy into the tissue region, or cannula with an interior lumen for conveying fluid to and from the tissue region, or a sensor for sensing temperature conditions in the tissue region.
3. A medical probe device for contacting tissue within the body, the device comprising a catheter tube having a control end and a probe end, the probe end including a housing having a port, an element mounted for rotation within the housing and movable between a first position confined within the housing and a second position extending through the port outside the housing, the element having a threaded exterior with a distal tip adapted to pene- trate a tissue region in response to rotation of the element during movement between the first and second position, the element comprising an electrode for emitting electromagnetic radio frequency energy into the tissue region, or cannula with an interior lumen for conveying fluid to and from the tissue region.
4. A method for ablating tissue within the body comprising the steps of introducing a catheter tube having a con¬ trol end and a probe end in the body, the probe end including a housing and an element within the hous¬ ing movable between a first position confined within the housing and a second position extending outside the housing, the element having a distal tip adapted to penetrate a tissue region during movement between the first and second position, the element being in the first position during introduction in the body, placing the probe end in contact with a tissue region, moving the element from the first position to the second position to penetrate the contacted tissue region, ablating the tissue region, while the ele¬ ment penetrates it, by either emitting electromag¬ netic radio frequency energy through the element into the tissue region or conveying ablation fluid through a lumen in the element for discharge into the tissue region.
PCT/US1995/012257 1994-09-30 1995-09-26 Systems and methods for ablating body tissue WO1996010367A1 (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0878167A3 (en) * 1997-04-11 1999-01-13 United States Surgical Corporation Rf ablation apparatus and controller therefor
US6402742B1 (en) 1997-04-11 2002-06-11 United States Surgical Corporation Controller for thermal treatment of tissue
WO2005107621A1 (en) * 2004-04-23 2005-11-17 Boston Scientific Scimed, Inc. Invasive ablation probe with non-coring distal tip
US7182762B2 (en) 2003-12-30 2007-02-27 Smith & Nephew, Inc. Electrosurgical device
EP1769762A1 (en) * 1997-04-11 2007-04-04 United States Surgical Corporation Rf ablation apparatus and controller therefor

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5007908A (en) * 1989-09-29 1991-04-16 Everest Medical Corporation Electrosurgical instrument having needle cutting electrode and spot-coag electrode
US5178620A (en) * 1988-06-10 1993-01-12 Advanced Angioplasty Products, Inc. Thermal dilatation catheter and method
US5259395A (en) * 1992-01-15 1993-11-09 Siemens Pacesetter, Inc. Pacemaker lead with extendable retractable lockable fixing helix
US5336222A (en) * 1993-03-29 1994-08-09 Boston Scientific Corporation Integrated catheter for diverse in situ tissue therapy
US5342357A (en) * 1992-11-13 1994-08-30 American Cardiac Ablation Co., Inc. Fluid cooled electrosurgical cauterization system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5178620A (en) * 1988-06-10 1993-01-12 Advanced Angioplasty Products, Inc. Thermal dilatation catheter and method
US5007908A (en) * 1989-09-29 1991-04-16 Everest Medical Corporation Electrosurgical instrument having needle cutting electrode and spot-coag electrode
US5259395A (en) * 1992-01-15 1993-11-09 Siemens Pacesetter, Inc. Pacemaker lead with extendable retractable lockable fixing helix
US5342357A (en) * 1992-11-13 1994-08-30 American Cardiac Ablation Co., Inc. Fluid cooled electrosurgical cauterization system
US5336222A (en) * 1993-03-29 1994-08-09 Boston Scientific Corporation Integrated catheter for diverse in situ tissue therapy

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0878167A3 (en) * 1997-04-11 1999-01-13 United States Surgical Corporation Rf ablation apparatus and controller therefor
US6402742B1 (en) 1997-04-11 2002-06-11 United States Surgical Corporation Controller for thermal treatment of tissue
EP1769762A1 (en) * 1997-04-11 2007-04-04 United States Surgical Corporation Rf ablation apparatus and controller therefor
US7182762B2 (en) 2003-12-30 2007-02-27 Smith & Nephew, Inc. Electrosurgical device
WO2005107621A1 (en) * 2004-04-23 2005-11-17 Boston Scientific Scimed, Inc. Invasive ablation probe with non-coring distal tip
US8142427B2 (en) 2004-04-23 2012-03-27 Boston Scientific Scimed, Inc. Invasive ablation probe with non-coring distal tip
US8632538B2 (en) 2004-04-23 2014-01-21 Boston Scientific Scimed, Inc. Invasive ablation probe with non-coring distal tip

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