Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N1/00—Electrotherapy; Circuits therefor
  • A61N1/18—Applying electric currents by contact electrodes
  • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
  • A61N1/38—Applying electric currents by contact electrodes alternating or intermittent currents for producing shock effects
  • A61N1/39—Heart defibrillators
  • A61N1/3956—Implantable devices for applying electric shocks to the heart, e.g. for cardioversion
  • A61N1/3962—Implantable devices for applying electric shocks to the heart, e.g. for cardioversion in combination with another heart therapy
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N1/00—Electrotherapy; Circuits therefor
  • A61N1/18—Applying electric currents by contact electrodes
  • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
  • A61N1/38—Applying electric currents by contact electrodes alternating or intermittent currents for producing shock effects
  • A61N1/39—Heart defibrillators
  • A61N1/3906—Heart defibrillators characterised by the form of the shockwave
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N1/00—Electrotherapy; Circuits therefor
  • A61N1/18—Applying electric currents by contact electrodes
  • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
  • A61N1/38—Applying electric currents by contact electrodes alternating or intermittent currents for producing shock effects
  • A61N1/39—Heart defibrillators
  • A61N1/3925—Monitoring; Protecting
  • A61N1/3937—Monitoring output parameters
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N1/00—Electrotherapy; Circuits therefor
  • A61N1/18—Applying electric currents by contact electrodes
  • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
  • A61N1/38—Applying electric currents by contact electrodes alternating or intermittent currents for producing shock effects
  • A61N1/39—Heart defibrillators
  • A61N1/3987—Heart defibrillators characterised by the timing or triggering of the shock
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N1/00—Electrotherapy; Circuits therefor
  • A61N1/18—Applying electric currents by contact electrodes
  • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
  • A61N1/38—Applying electric currents by contact electrodes alternating or intermittent currents for producing shock effects
  • A61N1/39—Heart defibrillators
  • A61N1/395—Heart defibrillators for treating atrial fibrillation

Definitions

• This invention is directed to the electrical management of cardiac arrhythmias or abnormal heart rhythms that occur in the electrical systems of the atrial or ventricular chambers of the human heart. More particularly, the invention is directed to subcutaneous implantable defibrillators and waveform energy control management.
• VF Ventricular fibrillation
• VF is a cause of cardiac arrest and sudden cardiac death.
• the ventricular muscle contracts in a much less organized pattern than during normal sinus rhythm, so the ventricles fail to pump blood into the arteries and systemic circulation.
• VF is a sudden, lethal arrhythmia responsible for many deaths in the Western world, mostly brought on by ischemic heart disease.
• VF which occurs in approximately 2 out of 10,000 people per year, is a medical emergency. If the arrhythmia continues for more than a few seconds, blood circulation will cease as evidenced by lack of pulse, blood pressure and respiration, and death will occur.
• Ventricular tachycardia is a tachyarrhythmia originating from an ectopic ventricular region, characterized by a rate typically greater than 100 beats per minute and wide QRS complexes.
• VT may be monomorphic, i.e., originating from a single repeating pathway with identical QRS complexes, or polymorphic, i.e., following changing pathways, with varying QRS complexes.
• Non-sustained VT is defined as an episode of tachycardia of less than 30 seconds duration; longer runs are considered sustained VT.
• VT VT
• rate greater than 100 beats per minute usually 150-200
• wide QRS complexes >120 ms
• presence of AV dissociation usually a AV that is integrated into the VT complex.
• fusion beats which are integrated into the VT complex.
• VT may develop without hemodynamic deterioration. Nevertheless, it often causes severe hemodynamic compromise and may deteriorate rapidly into VF. Therefore, this tachyarrhythmia also must be addressed swiftly to avoid morbidity or mortality.
• VT is defined as three or more beats of ventricular origin in succession at a rate greater than 100 beats per minute.
• the rhythm is usually regular, but on occasion it may be modestly irregular.
• the arrhythmia may be either well-tolerated or associated with grave, life-threatening hemodynamic compromise.
• the hemodynamic consequences of VT depend largely on the presence or absence or myocardial dysfunction (such as might result from ischemia or infarction) and on the rate of VT.
• AV dissociation usually is present, which means that the sinus node is depolarizing the atria in a normal manner at a rate either equal to, or slower than, the ventricular rate.
• sinus P waves sometimes can be recognized between QRS complexes.
• VT can also result from antiarrhythmic medications (an undesired effect) or from altered blood chemistries (such as low potassium or magnesium levels), pH (acid-base) changes, or insufficient oxygenation.
• Atrial arrhythmias such as atrial fibrillation (AF) and atrial tachycardia (AT) are abnormal heart rhythms which afflict around three million people each year in the United States.
• the most prevalent electrical manifestation of the disease electrically is a preponderance of irregular AF wavelets of activation.
• These irregular AF wavelets are frequently generated in the pulmonary veins (PVs) and are conducted into the left atrium and then the right atrium, causing chaotic and rapid activation that interferes with the normal sino-atrial and atrio-ventricular (SA/AV) node cardiac electrical pathways and generates rapid, irregular ventricular contractions.
• PVs pulmonary veins
• SA/AV sino-atrial and atrio-ventricular
• AF wavelets can be in the form of AF or atrial flutters, typical and atypical, which may vary in terms of severity and rate.
• AF makes the ventricular response so irregular and fast that it interferes with normal blood flow through the heart chambers, can lead to severe structural heart disease, and can be life-threatening if not treated effectively. While the irregular rate of ventricular contraction during AF and AT may compromise cardiac output and cause fatigue, much of the increased mortality associated with AF is due to clot formation resulting from poor circulation in the atria that embolizes to cause stroke, renal infarcts, etc. Persistent AF over weeks or months is particularly dangerous.
• a procedure to treat AF, or AT is DC cardioversion shock therapy to convert AF/flutter to sinus rhythm. This is an excellent conversion tool; however, unless the underlying cause of the AF is resolved, it most likely will recur.
• Implantable cardioverter defibrillators ICDs
• Modern ICDs operate basically by using a high voltage capacitor discharge which consists of four IGBT or MOSFET saturated switches in an H-bridge configuration which produces a biphasic truncated exponential (BTE) waveforms.
• phase 1 positive waveform This consists of a phase 1 positive waveform and a phase 2 negative waveform that makes up the BTE waveform.
• BTE waveform may vary between brands. However, this would be relative to peak voltage for phase 1, the tilt angle or decay of the capacitor discharge, and the pulse- width variability of phase 1 and phase 2.
• the anode lead is generally inserted in the RV at the apex or most distal end of the RV heart chamber.
• the cathode is generally the "Hot Can" which is the ICD case.
• phase 1 pulse width which minimizes the tilt or rate of decay or discharge from the capacitors.
• total pulse width is adjusted in an attempt to maintain the tilt angle of phase 1 by narrowing the phase 1 pulse width in an attempt to maintain as constant energy delivery as possible.
• phase 2 known as the hyperpolarization phase
• the pulse is generated by truncating or fast switching from one pair of IGBTs to the second pair which switches the remaining energy stored in the capacitor(s) negative with respect to EP zero.
• the remaining energy is delivered and usually presented by an appearance of having approximately one half the peak voltage of phase 1 and is conducting until the
• phase 1 and phase 2 peak voltages and time periods Different manufacturers have made their own calculations and their own determinations regarding phase 1 and phase 2 peak voltages and time periods.
• the only dynamic, "real time" adjustments that can be made on- the-fly during a cardioversion or defibrillation shock is the ability to (1) measure the impedance of the cardiac muscle, and (2) change the phase 1 and phase 2 pulse widths in an attempt to adjust and hold up the tilt angle, particularly of phase 1, that will statistically most effectively and reliably cardiovert and/or defibrillate.
• These waveforms contain a fast leading edge rise time from zero to about +600 to +800 V-DC. However, the remainder phase 1 and 2 waveforms are descending in nature, that is, they deliver decreasing energy with increasing time.
• ICD subcutaneous implantable cardio defibrillator
• SIMD subcutaneous implantable cardio defibrillator
• ICD transvenous pacing anti-tachycardia pacing (ATP)
• ATP anti-tachycardia pacing
• cardioversion cardioversion
• defibrillation using a single- wire, amplifier-based system.
• an amplifier-based external defibrillation and or cardioversion system can deliver arbitrary waveforms, including ascending ramp, ascending exponential, level, curved or any other waveform for phase 1 and phase 2 which are useful in the science of defibrillation and cardioversion.
• phase 1 and phase 2 arbitrary waveforms may be mixed and matched to ensure a higher rate of conversion.
• phase 2 pulse widths between one and about three milliseconds to hyperpolarize the myocardium after the phase 1 shock has been delivered.
• narrow phase 2 pulse widths of any arbitrary geometry may be employed for phase 2 such as ascending ramp, ascending exponential, level, curved or any other waveform that hyperpolarize the myocardium after the phase 1 shock has been delivered.
• a method and system are directed to the delivery of unique arbitrary biphasic ascending phase 1 and phase 2 waveforms, cardioversion and defibrillation shocks which employ (1) constant current, (2) constant voltage, or (3) constant energy modes of operation.
• a system uses unique waveform control whereby the ascending waveform shocks are delivered using unique ascending phase 1 and phase 2 waveforms, cardioversion and defibrillation shocks which employ (1) constant current, (2) constant voltage, or (3) constant energy modes of operation using software commands as to change the total energy within the shock waveform without changing peak voltage of the waveform.
• Examples include chopping the ascending waveforms in some portion of (most favorably) phase 1, that is, turning the waveform on and off at a rate which does not affect defibrillation or cardioversion performance, but does reduce energy consumed from the power supply and battery as well as minimizes the power dissipation within the power electronics within an ICD or SICD.
• Another aspect of the invention is the formation of ascending curved waveforms with a plateau during the last one to two milliseconds of the ascending waveform whereby changing the curve will change the delivered energy within the waveform and is performed through software commands that do not change the peak voltage or pulse width, but do change the energy delivered and used.
• Another aspect of the invention is directed to use of an amplifier array wherein each amplifier is driven differentially for the purpose of creating high voltage/high current ascending shocks via software commands.
• Another aspect of the invention is directed to a method and system for creating phase 2 waveforms whereby the shock voltage is "hard- switched" negative with respect to the zero crossing point to any specified negative voltage potential, and preferably, using narrow pulse widths between one and three milliseconds to
• Another aspect of the invention is directed to a method and system for creating phase 2 waveforms whereby the shock voltage is delivered as ascending ramp, chopped, curved square, rectilinear or level arbitrary waveforms that are negative with respect to the zero crossing point to any specified negative voltage potential, and preferably, using narrow pulse widths between one and four milliseconds to
• a cardiac defibrillation and or cardioversion waveform energy control system using differentially driven amplifier circuit topologies for the purpose of controlling delivered defibrillation and/or cardioversion electrical shocks to convert cardiac arrhythmias that include atrial fibrillation (AF), atrial tachycardia (AT), ventricular fibrillation (VF) or ventricular tachycardia (VT).
• the biphasic arbitrary shock waveforms deliver increasing and or level energy with increasing time as represented by phase 1 ascending ramp, ascending exponential, ascending chopped, ascending stepped, ascending curved, square, boot- shaped, rectilinear or level and/or any combination of geometric-shaped ascending or level waveforms.
• phase 2 any arbitrary waveform may be employed: ascending negative or descending negative, any pulse- width geometry or tilt may be selected using software commands.
• the phase 1 and phase 2 selections may be "hard switched" as a simple capacitive discharge, BTE, or shaped as a perfect rectilinear negative waveform in such a fashion where the drive is operating in a hybrid mode.
• Any arbitrary waveform may be delivered, and phase 1 may be a completely different waveform than phase 2.
• the ability to mix and match phase 1 and phase 2 waveforms may be useful in the art and science of
• cardioversion/defibrillation may be delivered by selecting one of three amplifier operational modes for software-controlled defibrillation and or cardioversion shock waveforms which are (1) constant current, (2) constant voltage, or (3) constant energy to manage delivered shock energies by changing the curve and or slope of ascending shocks to control delivered energy without changing peak voltage or phase 1 pulse width of a defibrillation or cardioversion shock.
• three amplifier operational modes for software-controlled defibrillation and or cardioversion shock waveforms which are (1) constant current, (2) constant voltage, or (3) constant energy to manage delivered shock energies by changing the curve and or slope of ascending shocks to control delivered energy without changing peak voltage or phase 1 pulse width of a defibrillation or cardioversion shock.
• an ICD or SICD differentially-driven amplifier system comprises an apparatus for treating VF or VT which employs biphasic shock waveforms which deliver increasing and or level energy with increasing time as represented by phase 1 ascending ramp, ascending exponential, ascending chopped, ascending stepped, ascending curved, square, rectilinear or level and or any combination of geometric shaped ascending waveforms.
• biphasic shock waveforms which deliver increasing and or level energy with increasing time as represented by phase 1 ascending ramp, ascending exponential, ascending chopped, ascending stepped, ascending curved, square, rectilinear or level and or any combination of geometric shaped ascending waveforms.
• These may be delivered by any one of the three amplifier operational modes for software-controlled defibrillation and or cardioversion shock waveforms which are (1) constant current, (2) constant voltage, or (3) constant energy for the purpose of controlling delivered defibrillation and or cardioversion electrical shocks to convert cardiac arrhythmias.
• an apparatus is an SICD case or "hot can" installed under the skin on the left chest side in the rib area, and having a lead wire with one or more distal shocking coils which travels between intercostal rib spaces traversing vertically along the left line/edge of the sternum. Shocks are delivered between the hot can and the distal coil electrode(s) for the purpose of defibrillation or cardioversion to change the transmembrane potential in the left and right ventricle sufficiently to convert VF or VT.
• an ICD transvenous differentially- driven amplifier system comprises both a method and apparatus for treating cardiac pacing disorders and defibrillation and/or cardioversion.
• a single- wire right ventricle pacing lead wire and shocking coil provides primary pacing, ATP, and
• defibrillation/cardioversion installed within the apex of the right ventricle endocardially.
• the software-directed system commands the amplifier circuits to provide the selected cardiac pacing, current sensing, anti-tachycardia pacing (ATP), and ventricular defibrillation and or ventricular cardioversion.
• Conventional pacing/defibrillation ICD systems use a complex insulated combination of isolated pacing wires and defibrillation or cardioversion high voltage shocking lead wire and coil assembly, which are embedded into the apex endocardially in the right ventricle and are prone to leads breaking prematurely.
• One- wire ICD defibrillation or cardiovesion shocking and transveous pacing therapy as described herein use amplifier circuits that are capable of delivering high voltage defibrillation and/or cardioversion shocking as well as pacing and ATP therapy, all using one wire.
• Traditional ICD devices use a separate high voltage shocking wire integrated with an insulated set of pacing and sense wires which deliver the pacing and ATP therapies.
• the reason amplifier-based or amplifier technology lends itself well to a one- wire high voltage shock and pacing therapies is that a well designed amplifier using modern day components can reproduce any voltage waveforms or pulses from a microprocessor from microvolts up to about 2000 V within one amplifier circuit or two amplifier circuits which are driven differentially, such as an ICD cardiac device.
• the amplifier ICD transvenous circuits sample the pacing current at the amplifier to make adjustments for capture and deliver the novel concept of using ascending or level constant current, constant voltage, or constant energy pacing pulses required by an electrophysiologist to manage bradycardia (unacceptable slow heart rates) as well as deliver anti-tachycardia pacing therapies.
• input voltages can be driven at the amplifier input to raise the voltage to very high voltages that are required for
• broken lead wires particularly broken pacing wires, have been a significant problem and costly in terms of patient costs and recall of failed wires involved with ICD lead implants.
• Using a one-wire shocking and pacing system has great advantages since the high voltage shocking lead is typically more robust than the insulated pacing wires.
• the SICD system described herein is not indicated for patients who require anti-bradycardia pacing or for those with heart failure for whom cardiac resynchronization is indicated.
• the device can deliver post-shock pacing therapy, but in doing so, it also paces the muscle wall, which can be uncomfortable in conscious patients. It cannot provide anti-tachycardia pacing, which can painlessly terminate ventricular tachycardia, and is not designed to treat ventricular arrhythmias at rates lower than 170 bpm.
• the use of lead anchoring sleeves mitigates the risk of subcutaneous lead migration.
• SICDs are as effective as standard transvenous devices in terminating induced ventricular fibrillation, although with higher energy requirements (37 J + 20 J for SICD vs. 11 + 9 J for transvenous ICD); the higher impedance and greater distance from the heart inherent in subcutaneous systems increases the energy requirements
• SICDs are not capable of pacing or delivering ATP for issues like bradycardia except at transcutaneous levels which can be very painful to the patient.
• the amplifiers can deliver a constant current into any load impedance by sampling the impedance characteristics of the signal which in this case is an ascending waveform.
• the ideal output waveform is constructed from discrete points in time or equations stored in the uC. At each discrete time point, on the order of microseconds, the uC outputs a new waveform value thru a Digital to Analog converter (DAC) to the amplifiers.
• DAC Digital to Analog converter
• the current through the load is digitally converted using an Analog to Digital converter (ADC).
• ADC Analog to Digital converter
• This digitized current is averaged over multiple time samples to create a rolling average.
• This rolling current average is used by the uC to calculate power and energy in real time for each discrete time point of the ideal output waveform.
• the uC then increases or decreases the ideal output waveform to maintain the desired constant current or to achieve the desired total energy at the completion of the waveform.
• a cardiac defibrillation or cardioversion waveform energy control system for treating cardiac arrhythmias in a patient, comprises differentially driven amplifier circuit operational modes to control the delivery of defibrillation or cardioversion electrical shocks, wherein the shock waveforms are constant current, constant voltage, or constant energy.
• a cardiac defibrillation or cardioversion waveform energy control system comprises differentially driven amplifier circuit operational modes to control the delivery of defibrillation or cardioversion electrical shocks, wherein the shock waveforms are constant current, constant voltage, or constant energy.
• the cardiac arrhythmias are atrial fibrillation (AF), atrial tachycardia (AT), ventricular fibrillation (VF), or ventricular tachycardia (VT).
• AF atrial fibrillation
• AT atrial tachycardia
• VF ventricular fibrillation
• VT ventricular tachycardia
• biphasic arbitrary shock waveforms deliver increasing and or level energy with increasing time as represented by phase 1 ascending ramp, ascending exponential, ascending chopped, ascending stepped, ascending curved, square, rectilinear or level and or any combination of geometric shaped ascending or level waveforms.
• selection of defibrillation or cardioversion shock waveform modes and delivery of the shocks is software-controlled.
• unique arbitrary biphasic ascending phase 1 and phase 2 waveforms are delivered, which arbitrary waveforms deliver increasing and or level energy with increasing time.
• the system is an implantable cardio defibrillator or a subcutaneous implantable cardio defibrillator.
• the system is a transvenous ICD, single- wire implantable cardiodefibrillator.
• a transvenous single-wire system delivers both the pacing voltages and the defibrillation/-cardioversion shocks are delivered within the right ventricle, which simplifies the system and reduces the possibility of broken pacing wires.
• the system is a subcutaneous implantable cardio defibrillator (SICD) with a subcutaneously extending lead wire.
• the system or method provides safer, more efficient arbitrary waveforms in a process which delivers increasing and/or level energy with increasing time, and thus lower peak voltages and slower rates of change are employed.
• the system comprises class A to Z or any other class of amplifier circuit topology to process arbitrary ascending or level waveforms that deliver increasing energy with increasing time for a positive phase 1 and negative energy for phase 2 time periods that can range from about 500 ns to about 100 ms pulsed, chopped, stepped, or continuous waveforms using any voltage for phase 1 and phase 2 from about 0 V to +/- 1500 VDC.
• the system comprises class A to Z or any other class of amplifier in cardioversion or defibrillation transvenous ICD or SICD systems to process arbitrary waveforms that deliver increasing energy with increasing time for a positive phase 1 and negative energy for phase 2 where only the highest power dissipation portion of the waveform is pulsed or chopped to reduce power dissipation in the electronic output circuits and component devices of cardioversion/defibrillation for ICD or SICD systems using software commands.
• the system comprises class A to Z or any other class of amplifier in cardioversion or defibrillation for transvenous ICD or SICD systems for controlling phase 2 waveforms whereby the waveform is "hard- switched" from the zero crossing point to a negative voltage potential as specified by software commands and as a minimum pulse width from about one to about three milliseconds, and whereby ascending arbitrary waveforms are delivered using lower peak voltages and creating shock vectors that optimize efficiency and safety during defibrillation of VF and VT.
• a system for a dynamic amplifier-based transvenous ICD or SICD system is controlled via software commands and is capable of delivering all known BTE shock waveforms with any tilt angle specified via software in addition to thousands of protocols using ascending waveforms which offer constant energy, constant voltage or constant current modes of operation which are unique and novel to the field.
• any ascending arbitrary waveform within the limits of the stored energy within a transvenous ICD or SICD may be delivered using software commands, enabling this system to maximize the reduction in damage to the heart and have the highest statistical cardioversion and defibrillation rate.
• the amplifier-based ICD or SICD system using software commands can deliver constant current, constant voltage or constant current modes in transvenous ICDs or subcutaneous SICDs.
• the amplifier-based system can be configured using software commands to deliver any ascending phase 1 waveforms and deliver a "hard switched" phase 2 waveform whereby the amplifiers are commanded to operate in a saturated switch mode that can deliver the phase 2 waveform as a fast vertical negative discharge from the remaining energy stored in the capacitor(s) and phase 1 can be an ascending waveform of any geometry and phase 2 may be switched negative relative to EP zero without any appreciable slope or ramp for the purpose of hyperpolarizing the syncytium of the heart using a narrow rectilinear waveform geometry which is most advantageous to defibrillation or cardioversion whereby this capability allows for a hybrid approach in that any phase 1 ascending or level geometry waveform may be employed in concert with any phase 2 waveform including fast rectilinear or hard switching phase 2 which provides for the ability to mix and match phase 1 and phase 2 waveform geometries giving the cardiologist/EP the most options to select from when treating patients that require a more sophisticated cardioversion/defibri
• the invention comprises a product possessing the features, properties, and the relation of components which will be exemplified in the product hereinafter described and the scope of the invention will be indicated in the claims.
• FIG. 1 represents a system diagram of an embodiment of the invention for an ICD
• FIG. 2 represents a system diagram of an embodiment of the invention for an SICD
• FIG. 3 is a representation showing placement of an amplifier-based SICD according to the invention.
• FIG. 4 is a representation showing placement of a transvenous ICD and a single RV transvenous pacing lead and shocking coil as a one-wire defibrillation cardioversion system according to the invention
• FIGS. 5 A to 5C represent examples of amplifier- generated ascending ramp shock waveforms delivered with constant voltage, constant current, and constant energy modes of operation, respectively, wherein impedance, voltage, current, and energy in Joules are delivered in each example shown.
• FIG. 6 is a representation of ramp and variable exponential curve waveforms for energy management, according to the invention.
• FIG. 7 is a representation of ramp and variable curve ascending exponential curve waveforms with reduced power dissipation chopped ascending waveforms for energy management, according to the invention.
• FIGS. 8 and 9 are copies of waveform scope tracings published in AHA
• FIGS. 10 to 12 each represent a waveform for power dissipation energy management control system, according to the invention.
• FIG. 1 The system diagram for an ICD represented by FIG. 1 illustrates one embodiment of an amplifier-based defibrillation or cardioversion system useful according to the invention.
• a battery 12 provides power to a pulse width modulated (PWM) and regulated DC/DC converter 16, which in turn distributes a control voltage to a microprocessor 18, which in turn sends a signal to an ECG Amp 20 and an ECG Sense Analyzer 22.
• DC/DC converter 16 also distributes high voltage to a capacitor circuit 28 and two amplifiers 30 and 32.
• a lead wire is implanted within the right ventricle, represented by chest impedance resistors 42, 44.
• Electrode 40 is a single wire that serves as the single pacing wire or ATP therapy, defibrillation, or cardioversion lead wire.
• Pacing sense circuit 24, ATP Amp 25, and sense resistors 48 and 49 make up the current feedback to microprocessor 18 for the one- wire pacing and ATP functions.
• FIG. 2 The system diagram for an SICD represented by FIG. 2 illustrates one embodiment of an amplifier-based defibrillation system useful according to the invention.
• a battery 52 provides power to a pulse width modulated (PWM) and regulated DC/DC converter 56, which in turn distributes a control voltage to a microprocessor 58, which in turn sends a signal to an ECG Amp 60 and an ECG Sense Analyzer 62.
• DC/DC converter 56 also distributes high voltage to a capacitor circuit 68 and two amplifiers 70 and 72.
• Ventricle Electrode 80 with a single wire serves as the single defibrillation or cardioversion wire.
• the apparatus is an SICD case or "hot can” 71 installed under the skin on the left chest side in the rib area, and having a lead wire with one or more shocking coils which travels between intercostal rib spaces traversing vertically along the left line/edge of the sternum, as shown in FIG. 3. Shocks are delivered between the hot can 92 and the distal coil electrode(s) 90 installed in a patient's chest area 94 for the purpose of defibrillation and or cardioversion so as to change the transmembrane potential in the left and right ventricle sufficiently to convert VF or VT.
• Pacing sense circuit 64 and sense resistors 82 and 84 make up the current feedback to the
• microprocessor 58 for the one wire pacing and shock functions.
• FIG. 4 a single RV pacing lead and shocking coil as a one wire 42 is embedded within the right ventricle apex 44 defibrillation cardioversion system, consistent with FIG. 1. If necessary, energy is delivered to the right ventricle to help it contract normally.
• FIGS. 5 A to 5C represent amplifier- generated ascending ramp shock waveform examples delivered with constant voltage, constant current, and constant energy modes of operation, respectively. Impedance, voltage and currents delivered in examples are shown.
• ramp and variable exponential curve waveforms for energy management are shown.
• ramp and variable curve ascending exponential curve waveforms with reduced power dissipation chopped ascending waveforms for energy management are shown.
• FIG. 8 represents an actual ascending ramp waveform scope tracing published in AHA Circulation, September 11, 2012.
• the ascending ramp DFT was 15 J for 8 msec phase 1
• the rectilinear phase 2 was 4 J for 3.5 msec phase 2.
• FIG. 9 represents an actual ascending ramp "power band” waveform scope tracing published in AHA Circulation, September 11, 2012.
• the phase 1 power dissipation in power output devices is 13.5 J.
• the shape of the power band for an ascending ramp waveform should be noted.
• FIG. 10 represents an ascending exponential ramp positive chopped portion half way up the ramp for a power dissipation energy management control system. It is also characterized as an ascending ramp software burst control in output devices and into the heart.
• FIG. 11 represents an ascending exponential ramp negative curved chopped portion half way up the ramp for a power dissipation energy management control system. It is also characterized as an ascending ramp software burst control in output devices and into the heart.
• FIG. 12 represents an ascending exponential ramp equal curve chopped half way up the ramp for a power dissipation energy management control system. It is also characterized as an ascending ramp 50% pulsed waveform.

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