WO2015000500A1

WO2015000500A1 - Multiple catheter cardiac electrophysiology system

Info

Publication number: WO2015000500A1
Application number: PCT/EP2013/063822
Authority: WO
Inventors: Mads Emil Matthiesen; Rune PAAMAND
Original assignee: Cathvision Aps
Priority date: 2013-07-01
Filing date: 2013-07-01
Publication date: 2015-01-08
Also published as: WO2015000500A8

Abstract

The invention relates to a modular control unit for a multiple catheter cardiac electrophysiology (EP) system. The modular control unit comprises a common interface configured for communicating with a computer through a computer interface port, a first catheter control module configured for cardiac EP-diagnosis, and a second catheter control module configured for cardiac EP-diagnosis. The first and second catheter control modules each have circuitry comprising a catheter port configured for electrically connecting one or more electrodes of an EP-catheter to the circuitry, an EP-signal recorder comprising devices for amplifying and processing EP-signals received from the catheter port, a stimulation section for feeding a cardiac stimulation signal to the catheter port, and a module-microcontroller (MCU) configured for controlling the operation of the EP-signal recorder and the operation of the stimulation section. The first and second catheter control modules are galvanically isolated from each other and communicate with the common interface through a respective, galvanically isolated module interface port.

Description

MULTIPLE CATHETER CARDIAC ELECTROPHYSIOLOGY SYSTEM

TECHNICAL FIELD

The present invention relates in one aspect to a modular control unit for a multiple catheter cardiac electrophysiology (EP) system. In a further aspect, the invention relates to a cardiac electrophysiology (EP) workstation comprising such a modular control unit. In yet a further aspect, the invention relates to a method for measuring cardiac EP-signals received from separate EP-catheters introduced in a mammal body.

The invention relates to the field of cardiac electrophysiology performed using catheters inserted into a mammal body. The mammal body may be an animal or a human being, in the following collectively referred to as patient. BACKGROUND OF THE INVENTION

Diagnosis and treatment of serious heart diseases, such as tachycardial arrhythmia, has considerably evolved by using minimally invasive endocardial procedures, i.e. procedures in the heart performed using catheters inserted into a patient. A large variety of minimally invasive procedures for heart diseases have therefore been de- veloped in this field, the procedures including tasks of electrophysiology measurements, heart tissue stimulation/pacing, surgery and ablation. The electrophysiology (EP) catheters used in these procedures are long, flexible instruments with a distal portion for insertion into a patient and a proximal end equipped with means for handling and controlling the catheter. The EP-catheter may be provided with a mecha- nism for bending a distal tip of the catheter for steering and may comprise other means for advancing and positioning the distal tip to the inside of the heart. The catheter may be a dedicated instrument that is optimized for a given task or for a particular set of tasks. The distal portion of an EP-catheter for diagnostic purposes comprises one or more electrodes for sensing electrophysiological signals from the heart tissue, or for applying an electrical stimulus to the heart tissue for diagnostic purposes, e.g. for provoking or terminating a state of arrhythmia or for pacing the heart. In addition thereto, an EP-catheter may be configured for treatment of cardiac diseases by ablation. An EP-catheter configured for ablation comprises means for applying an energy dose sufficient for locally modifying heart tissue as e.g. required for treating a patient diagnosed for tachycardial arrhythmia. Such means may comprise electrodes for delivering high-frequency current to the heart tissue in a localized manner. At the proximal end, the catheter comprises an electrical interface through which the electrodes of the EP-catheter are electrically connected to circuitry for measuring and recording of EP-signals received from the EP-catheter, providing EP-stimulus and/or supplying ablation energy to the EP-catheter. The circuitry communicates with a computer which may comprise monitoring, processing and analysis tools, user interface, configuration and data display.

While being minimally invasive, these cardiac procedures are often complex and may involve multiple catheters inserted into the patient, and even multiple catheters reaching into the heart. These procedures are typically performed in an electrophys- iology (EP) laboratory, which in addition to electrophysiological equipment may further be equipped with a range of different instrumentation, such as for imaging, navigation/positioning of the catheters, diagnosis, and monitoring of the patient.

When performing multiple-catheter cardiac procedures, the physician is in practice also confronted with a need for a high level of configuration flexibility of the set-up in order to perform a sequence or number of different steps without having to remove and again position the different catheters. At the same time, a close surveillance and control of all patient information, procedure data and other parameters is required in order to guarantee the safety of the patient. Therefore the instrumentation of an EP- laboratory is advantageously combined into an integrated system.

A central issue in performing such procedures is the interference between different tasks. In particular, the quality, sensitivity and reliability of cardiac electrophysiology measurements may be strongly affected by tasks such as stimulating/pacing or ab- lating, or by artefacts resulting from the use of multiple catheters and the complexity of the set-up.

Therefore there is a need for an improved integrated EP-workstation for performing cardiac electrophysiological procedures using multiple catheters, which overcomes at least some of the above-mentioned disadvantages of the prior art or provides an alternative thereto.

SUMMARY OF THE INVENTION

According to one aspect of the invention, a modular control unit for a multiple catheter cardiac electrophysiology (EP) system is provided, the modular control unit comprising a common interface configured for communicating with a computer through a computer interface port, a first catheter control module configured for cardiac EP- diagnosis and a second catheter control module configured for cardiac EP- diagnosis, the first and second catheter control modules each having circuitry comprising a catheter port configured for electrically connecting one or more electrodes of an EP-catheter to the circuitry, an EP-signal recorder comprising devices for amplifying and processing EP-signals received from the catheter port, a stimulation section for feeding a cardiac stimulation signal to the catheter port, and a module- microcontroller configured for controlling the operation of the EP-signal recorder and the operation of the stimulation section, wherein the first and second catheter control modules are galvanically isolated from each other and wherein the first and second catheter control modules each communicate with the common interface through a respective, galvanically isolated module interface port.

The galvanic isolation of the individual modules includes a galvanically isolated power supply and galvanically isolated data/communication links. The galvanic isolation of the individual modules further includes galvanic isolation of the signal paths in and out of the module with the exception of EP-signal paths communicating with the module's circuitry through a direct metallic connection to EP-electrodes of e.g. an EP-catheter via the catheter port. Note that in a cardiac EP-system, the catheter port is also defibrillation protected.

In operation, the modular control unit is part of a multiple catheter cardiac electro- physiology system/workstation, wherein each EP-catheter may be associated with a respective module of the modular control unit. A distal portion of the EP catheters carrying one or more electrodes is inserted into the patient and brought into the vicinity of the heart depending on the procedure to be carried out. At their proximal ends the EP-catheters are connected to the catheter port of the respective module. A first EP-signal sensed by the electrodes of a first EP-catheter is received at the catheter port of the first module and passed on from the catheter port to the circuitry of the first module through a direct electrical connection. The circuitry comprises the EP-signal recorder, which receives and records the first EP-signal. The EP-signal recorder is configured to provide analogue signal processing/filtering and amplification, and typically comprises A/D conversion means for digitizing the analogue signal, thus converting the analogue EP-signal into digital EP-data representing the first EP-signal. The EP-signal recorder may further comprise digital signal processing means as well as memory for temporary storage of recorded EP-data. The recorded EP-data representing the first EP-signal is transferred from the first module to the common interface via the galvanic isolated module interface port of the first module.

The circuitry of the first module further comprises a stimulation section configured for providing a first cardiac stimulation signal to the circuitry. The first cardiac stimulation signal is passed to the catheter port and via the direct electrical connection applied to at least one electrode of the first EP-catheter for pacing or otherwise stimulating the tissue of the heart. The operation of the EP-signal recorder and of the stimulation section is controlled by the module-microcontroller in response to instructions received via the common interface from a central computer of the EP- system/workstation.

Accordingly, a second EP-catheter may be associated with the second catheter control module to perform cardiac EP-diagnosis procedures including endocardiac EP- measurements and stimulation/pacing tasks. As mentioned above, the catheter control modules each communicate with the common interface through a respective galvanically isolated module interface port to transmit recorded data and to receive instructions for operation from a central computer of the EP-system/workstation. The first and second catheter control modules are thus coupled to the common interface for data exchange and system control. The common interface may further comprise a common power supply with a separate, galvanically isolated power output for each of the catheter control modules. Performing cardiac EP-measurements implies detecting, amplifying and processing electrical signal levels in the range of 0.1-1 mV. The usefulness of the EP- measurements for diagnosis strongly depends on the quality of the recorded signal. This puts a severe challenge to the electronics for amplifying and processing the analogue EP-signals, and even to the components for converting the analogue EP- signals to digital EP-data. Furthermore, numerous noise sources may affect the EP- measurements. A prominent noise source is common mode noise, in particular when performing cardiac EP-procedures involving multiple catheters inserted into the patient. By including an EP-signal recorder within the galvanically isolated cir- cuitry of each catheter control module, wherein the EP-signal recorder comprises means for amplification and processing of the analogue EP-signals, common mode noise in the EP-signal amplification and processing stage stemming from the interaction between multiple EP-catheters is suppressed or at least largely reduced.

Another source of noise is noise created by fluctuations in reference voltage levels for the amplification and digital conversion components. Such fluctuations may be caused by induced noise or from fluctuations in power consumptions of components sharing the same power supply. Galvanic isolation of the power supply for each module may eliminate such sources of noise.

When using multiple EP-catheters in a patient, each EP-catheter may operate at a different local potential than any of the other EP-catheters. The EP-signals from different catheters may therefore comprise a substantial bias background component when measured with respect to a common reference in a common EP-signal recorder. While this bias component in itself may not be noisy, the bias may be large as compared to the levels of the EP-signals of interest in the range of 0.1-1 mV. The precision of the detection, amplification, and processing of the EP-signals from multiple EP-catheters by the same EP-recorder is therefore affected by this bias offset. Each of the multiple EP-catheters is associated with a respective galvanically isolated catheter control module including an EP-signal recorder within the circuitry of the catheter control module. Therefore, the bias offset due to different local potentials seen by the different catheters may be eliminated. Consequently, the precision of the detection, amplification, and processing of the EP-signals from multiple EP- catheters is improved. The EP-signals that are sensed by the different EP-catheters and recorded in the respective catheter control modules are transmitted to the common interface through the galvanically isolated module interface port, typically in the form of digitized EP-data representing the EP-signals. The EP-signals/data may then be combined for consolidation in a computer communicating with the common interface through the computer interface port of the modular control unit. This design/construction thus allows for performing EP-diagnosis procedures using multiple catheters with an improved common mode rejection and improved EP-signal recording.

Since diagnostic cardiac EP-procedures in addition to measuring EP-signals typically also involve applying an EP-stimulus to the heart tissue, e.g. for provoking or terminating a given pathological state, or for pacing the heart, a multiple catheter EP- system/workstation configured for cardiac EP-diagnosis should also provide a stimu- lation signal to the one or more electrodes of the multiple catheters. Therefore, the galvanically isolated circuitry of each of the catheter control modules is also equipped with a stimulation section for feeding a cardiac stimulation signal to the respective catheter port through a galvanic connection. By also including a stimulation section within the galvanically isolated circuitry of each catheter control module, the EP-system/workstation allows for performing EP-diagnosis procedures using multiple catheters with an improved common mode rejection and improved EP- signal recording.

Further according to one embodiment of the modular control unit, the stimulation section of at least two catheter control modules comprises a switching device for coupling a common stimulation source to the catheter port.

The switching devices are arranged between the catheter port of the module and the stimulation source. In an OFF-state' the switching devices galvanically separate the catheter port and the stimulation source. In an 'ON-state', the switching device establishes a galvanic connection between the catheter port and the stimulation source. A common stimulation source is connected to the switching devices of at least two catheter control modules. The switching devices of these catheter control modules are configured such that at any given time galvanic isolation of the catheter control module may be maintained with respect to any of the other catheter control modules. The stimulation source comprises or is connected to a stimulation generator, which preferably has a galvanically isolated power supply and is galvanically isolated from the circuitry of the catheter control modules apart from any connec- tions deliberately established through the switching devices.

The common stimulation source generates a cardiac stimulation signal at a stimulation output port and delivers the stimulation signal through a galvanic connection to the switching devices of the catheter control modules. The switching device of a given catheter control module may then be operated to establish a galvanic connection from the stimulation source output to the catheter port and further to the EP- electrodes of an EP-catheter associated with the given catheter control module. Thereby, the cardiac stimulation signal provided by the stimulation source may be applied to the patient through the EP-catheter associated with the given catheter control module.

Advantageously, the switching devices of the catheter control modules are controlled via the module-microcontroller of the respective catheter control module. The switching of a plurality of switching devices may be then be coordinated by the cen- tral computer via the common interface so as to perform switching operations without breaking the galvanic isolation between the modules. Accordingly, any other control functions performed by means of the module microcontrollers may be coordinated by the central computer via the common interface. According to one embodiment, the switching devices may be operated to deliberately establishing a galvanic connection between the individual catheter control modules, thereby forming a group of modules that are galvanically connected to each other, but galvanically isolated from any further catheter control modules not member of that group. Thereby an increased flexibility of use of the EP- system/workstation is achieved. For such a galvanically connected group of catheter control modules, the above-mentioned advantages of inter-modular galvanic isolation are then achieved with respect to the further catheter control modules. In one application of such grouping, the switching devices of a first catheter control module and a second catheter control module may be operated to simultaneously couple the common stimulation source galvanically to the catheter ports of both catheter control modules, thus simultaneously applying the stimulation signal through two separate catheters.

Further according to one embodiment of the modular control unit, the switching of all switching devices is coordinated through the common interface so as to only couple the common stimulation source to the catheter port of one module at a time while keeping the catheter ports of all remaining modules decoupled. Thereby galvanic isolation of the individual modules with respect to each other is ensured.

Further according to one embodiment of the modular control unit, the common stimulation source is a common stimulation generator provided within the modular unit. Thereby a compact unit for standalone use is achieved.

Further according to one embodiment of the modular control unit, the common stimulation source is a common stimulation input port configured for receiving a stimulation signal from an external stimulation generator. By providing the cardiac stimula- tion signal from an external stimulation generator connected to the modular control unit through a common stimulation input port a flexible EP-system/workstation is achieved, which allows for easy reconfiguration by replacing the external stimulation generator. Further according to one embodiment of the modular control unit, the stimulation section of at least two catheter control modules each comprises a stimulation generator. Thereby a compact modular control unit is achieved allowing for independent stimulation through separate catheters. Advantageously according to one embodiment of the modular control unit, the stimulation section of each catheter control module comprises a stimulation generator. Thereby it is achieved that the catheter ports of all catheter control modules may be used interchangeably for cardiac diagnostic purposes including EP-measurements and EP-stimulation/pacing tasks. Advantageously according to one embodiment of the modular control unit, the operation of all stimulation sections is coordinated through the common interface so as to couple a stimulation signal to the catheter port of only one catheter control mod- ule at a time. Thereby stimulation is restraint to be applied through a single catheter at a time.

Further according to one embodiment of the modular control unit, at least one of the modules comprises an ablation section for supplying ablation energy to the EP- catheter port. Thereby it is achieved that the catheter control module may be configured for use with a cardiac ablation EP-catheter, i.e. an EP-catheter adapted for cardiac ablation treatment. Said catheter control module may thus be used for performing ablation procedures and for performing EP-diagnosis procedures including cardiac EP-measurement tasks and cardiac stimulation/pacing tasks using the same ablation catheter.

Further according to one embodiment of the modular control unit, the ablation section comprises an ablation control device for coupling a common ablation source to the catheter port. Advantageously, the ablation control device may be arranged to operate in an analogous manner as the above-mentioned stimulation switching devices, merely adapted to handling the delivery of ablation energy from the ablation source to the catheter port.

Accordingly, the ablation control device is arranged between the catheter port of the module and the ablation source. In a 'DISABLE-state' the ablation control device galvanically separates the catheter port and the ablation source. In a 'ENABLE- state', the ablation control device establishes a galvanic connection between the catheter port and the ablation source. A common ablation source is connected to the ablation control devices of at least two catheter control modules. The ablation con- trol devices of these catheter control modules are configured such that at any given time galvanic isolation of the catheter control module may be maintained with respect to any of the other catheter control modules. The ablation source comprises or is connected to an ablation generator, which preferably has a galvanically isolated power supply and is galvanically isolated from the circuitry of the catheter control modules apart from any connections deliberately established through an ablation control device.

The common ablation source generates a cardiac ablation signal at an ablation source output and delivers the ablation signal to the ablation control devices of the catheter control modules. The ablation control device of a given catheter control module configured for ablation treatment may then be operated to establish a connection from the ablation source output to the catheter port and further to the ablation EP-catheter associated with the given catheter control module. The ablation signal carries an ablation energy suited for performing an ablation treatment of heart tissue. Different types of ablation signals are known in the art, such as RF-energy, laser light, etc. Depending on the type of ablation energy carried by the ablation signal, it may be required that the ablation control device establishes a galvanic connection between the ablation source and the catheter port. Thereby, the cardiac ablation signal provided by the ablation source may be applied to the patient through the ablation EP-catheter associated with the given catheter control module.

In case a plurality of ablation control devices are provided and associated with different catheter control modules, they are preferably controlled via the module- microcontroller of the respective catheter control module. The operation of a plurality of ablation control devices may further preferably be coordinated by the central computer via the common interface so as to perform ablation procedures without undesired interference between the catheter control modules. Accordingly, any other control functions performed by means of the module microcontrollers may be coor- dinated by the central computer via the common interface.

Further according to one embodiment of the modular control unit, the common ablation source is a common ablation input port configured for receiving ablation energy from an external ablation generator. By providing the cardiac ablation signal from an external ablation generator connected to the modular control unit through a common ablation input port a flexible EP-system/workstation is achieved, which allows for easy reconfiguration by replacing the external ablation generator. Further according to one embodiment, the modular control unit further comprises relay means, said relay means having a common line and at least a first switch, said first switch being adapted to electrically connect an electrode line of a first catheter control module to the common line.

The one or more electrodes of a first EP-catheter may be connected to a first catheter control module via respective electrode lines. At least one electrode line is connected to the common line via the relay means. The common line is floating. The relay means comprises a switch that is operable between an ΌΝ'-state and an 'OFF'-state, wherein in the ΌΝ'-state, the first electrode line is electrically connected to the common line, and wherein in the 'OFF'-state, the first electrode line is disconnected from the common line. In the 'OFF'-state, the common line may float at one potential and the first electrode line may float at a different potential. By setting the switch to the ΌΝ'-state, the common line and the electrode line are forced to float at the same potential. Thereby, the corresponding electrode of the first EP-catheter that is connected to the first catheter control module may be forced to float at the same potential as the common line.

Preferably, the relay means are operable from the central computer via a galvanical- ly isolated link, e.g. through the common computer interface of the modular control unit. The switches may e.g. be provided as switching devices on the catheter control modules or as switching devices in a separate relay module within the modular control unit. It may also be conceived to provide the switches in a relay module that is external to the modular control unit, wherein switches of the relay means are ar- ranged to intercept the electrode lines between the EP-catheter and the catheter port.

Further according to one embodiment, the relay means further comprise at least a second switch, said second switch being adapted to electrically connect an elec- trode line of a second catheter control module to the common line.

By coupling the electrode lines of two or more catheter control modules to the common line, the electrode lines are forced to the same potential. Consequently, the concerned catheter control modules are galvanically grouped together. Note, how- ever, that the galvanically grouped catheter control modules form a galvanic entity that still is galvanically isolated and thus floating with respect to its environment.

Further according to one embodiment of the modular control unit, the relay means further comprises a reference switch, said reference switch being adapted to electrically connect an external reference line to the common line. By coupling the common line to the external reference line the potential of the common line, and as case may be of the electrode lines coupled to it, can be forced to follow an externally controlled reference potential. The externally controlled reference potential shall be as- sociated with the "measuring object" for the EP-diagnosis, i.e. a reference potential derived from the patient.

Advantageously according to the invention, the external reference line is connected to a Wilson Central Terminal (WCT) arrangement of electrodes. Advantageously the electrodes of the WCT-arrangement are a plurality of resistively coupled body surface electrodes for attachment to the patient.

Further according to one embodiment, the electrode lines are reference electrode lines.

In a given EP-catheter, the electrophysiological signal may be measured as a voltage between a probing electrode and a reference electrode. By coupling the reference electrode of the EP-catheter to the common line, the potential probed by the probing electrode is referred to the common potential of the common line. EP- catheters coupled to different catheter control modules are galvanically isolated from each other apart from any resistive path through the patient. EP-signals probed by electrodes on EP-catheters connected to different catheter control modules can therefore usually not be directly referred to each other. By coupling the reference electrode lines of two or more catheter control modules to the common line, the ref- erence electrode lines are forced to the same potential. Consequently, the concerned catheter control modules are galvanically grouped together, and EP-signals probed by electrodes from different EP-catheters can now be referred to each other. Thereby, a highly flexible EP-workstation is achieved that combines the above- mentioned advantages of galvanically isolated catheter control modules with the possibility of performing inter-catheter EP-diagnostic procedures by grouping catheter control modules together as required or desired. As mentioned above, the configuration may advantageously be centrally controlled by the computer of the EP- workstation. In order to add to the ease of use and to the safety of the EP- workstation, the system may comprise software-implemented configuration rules. These configuration rules may e.g. concern pre-defined EP-procedures and/or safety limitations. For example, at an operator level only pre-programmed configurations may be re-called from memory, whereas new procedures requiring new configurations may be implemented only at a programming level.

Accordingly, computer controlled relay means may be used for selectively coupling an external stimulation source to a selected catheter control module, wherein a first stimulation relay means may be provided for selectively coupling a probe electrode of a selected EP-catheter to the positive terminal of the external stimulation source, and a second stimulation relay means cooperating with the first may be provided for simultaneously coupling the respective reference electrode of the selected EP- catheter to the negative terminal of the external stimulation source. As in the above- mentioned embodiment, software-implemented configuration rules may be provided to ensure safe operation in agreement with approved EP-procedures. Generally, when operating a switch to couple two independently floating entities together, such as coupling an external stimulation source to the probe and reference electrodes lines of a galvanically isolated catheter control module, a substantial disturbance of the electrical signals may arise. Advantageously, the switching devices may comprise an electrical coupling filter suppressing or at least damping any sudden changes to allow for a "soft" coupling of the two entities. A simple example for such a coupling filter is an R-C-element, such as an R-C-element with a cut-off frequency of about 80 Hz.

According to a further aspect of the invention, a cardiac electrophysiology (EP) workstation comprises a modular control unit according to any of the above- mentioned embodiments, the EP-workstation further comprising a first EP-catheter connected to the catheter port of the first catheter control module, and a second EP- catheter connected to the catheter port of the second catheter control module, and a central computer system communicating with the modular control unit through the computer interface port of the common interface.

Further according to one embodiment of the cardiac EP-workstation, said central computer system is further configured for controlling external devices, said external devices comprising devices selected from the group of display devices, user interfaces, external stimulation generators, external ablation generators, medical imaging equipment, catheter navigation and positioning instrumentation, patient monitoring equipment, and patient data storage.

According to a yet further aspect, the present invention provides a method for measuring cardiac EP-signals received from separate EP-catheters introduced in a mammal body, the method comprising

passing a first EP-signal from a first EP-catheter through a defibrillation protected catheter port to a first EP-signal recorder in a first catheter control module, processing the first EP-signal in the first EP-recorder to obtain a first processed EP- signal,

passing a second EP-signal from a second EP-catheter through a defibrillation protected catheter port to a second EP-signal recorder in a second catheter control module, wherein the second catheter control module is galvanically isolated from the first catheter control module,

processing the second EP-signal in the second EP-recorder to obtain a second processed EP-signal, and

passing the first and second processed EP-signals from the first and second cathe- ter control modules through galvanically isolated links to a common interface for combined analysis of the processed EP-signals.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, detailed embodiments of the invention are described with reference to the appended drawings. The drawings show in

FIG. 1 a cardiac electrophysiology (EP) workstation comprising a modular control unit according to one embodiment of the invention, FIG. 2 a diagrammatic view of the architecture of a modular control unit according to one embodiment of the invention,

FIG. 3 a diagrammatic view of the architecture of a modular control unit according to another embodiment of the invention.

FIG. 4 a schematic view of a further embodiment of a modular control unit according to the invention with reference relay means,

FIG. 5 a schematic view of yet a further embodiment of a modular control unit according to the invention with reference relay means and stimulation relay means, and in

FIG. 6 a schematic view of a soft switching device according to one embodiment of a modular control unit.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG. 1 shows an EP-workstation 1 for performing cardiac electrophysiology (EP) procedures on a patient. Such a workstation may be operated e.g. in an EP- laboratory for diagnosing and treating patients for cardiac diseases related to the electrophysiological properties of the heart, such as arrhythmia. The EP-workstation 1 comprises a modular control unit 2 with four catheter control module. Each catheter control module has a catheter port 3 to which an EP-catheter 10 may be connected. The modular control unit communicates with a central computer 4 which presents user interface means 5, 6 and display means 7, 8 to a user of the EP- workstation 1. The EP-catheter 10 is configured for cardiac EP-diagnosis and has a distal portion 1 1 for insertion into a mammal body (patient, not shown). Electrodes provided at a distal end 12 of the catheter 1 1 may be advanced to the heart for sensing cardiac EP-signals and/or providing stimulation/pacing pulses to the heart tissue. A proximal portion 13 of the EP-catheter comprises a handle 14 for controlling/steering the catheter 10 by the user of the EP-workstation and is connected to the catheter port 3 via cable connection 15. Only one catheter is shown in Fig. 1. However, further EP-catheters 10 may be connected to the further catheter ports 3 of the modular control unit, each further EP- catheter being associated with a further catheter control module, which is galvanical- ly isolated from the other catheter control modules. The EP-workstation of Fig. 1 further comprises an external stimulation generator 16 providing a stimulation output, which may be individually coupled to one of the catheter ports 3 at a time through switching devices comprised in the galvanically isolated circuitry of the respective catheter control modules. At least one of the EP-catheters connected to the modular control unit 2 may be adapted for performing ablation treatment. The required ablation energy may be provided through the associated catheter control module at the corresponding catheter port 3. Alternatively, the ablation energy is provided directly to the EP- catheter from a galvanically isolated ablation source which is controlled from the computer 4 via a galvanically isolated link to maintain the galvanic isolation of the catheter / catheter control module ensemble.

The block diagram in FIG. 2 shows schematically the architecture of a modular control unit 100 for use in a cardiac EP-workstation according to one embodiment of the invention. The modular control unit comprises a first catheter control module 1 10, a second catheter control module 120, and a common interface 130 with a computer interface port 131 for communication with a computer. The catheter control modules 1 10, 120 are both configured for EP-diagnosis including circuitry for receiving and recording EP-signals, as well as for providing cardiac stimulation/pacing signals.

The first catheter control module 1 10 comprises a catheter port 1 1 1 configured for electrically connecting one or more electrodes of an EP-catheter 10 to its circuitry. The direct electrical connections between the electrodes in contact with the patient and the circuitry of the first catheter control module 1 10 comprise a defibrillation protection circuit 1 12. The first catheter control module 1 10 further comprises an EP-signal recorder 1 13 with devices for amplifying and processing EP-signals received from the catheter port 1 1 1 , a stimulation section 1 15 for feeding a cardiac stimulation signal to the catheter port 1 1 1 , and a module-microcontroller (MCU) 1 14 configured for controlling the operation of the EP-signal recorder 1 13 and the opera- tion of the stimulation section 1 15. In this embodiment, a stimulation generator for generating the cardiac stimulation signal is integrated in the stimulation section 1 15 of the first catheter control module 1 10. The first catheter control module 1 10 communicates with the common interface 130 through a galvanically isolated module interface port 1 16. The common interface 130 may further provide power to the first catheter control module 1 10 through a galvanically isolated module power supply 1 17.

Likewise, the second catheter control module 120 comprises a catheter port 121 configured for electrically connecting one or more electrodes of an EP-catheter 20 to its circuitry, wherein the catheter port has a defibrillation protection 122. The second catheter control module 120 further comprises an EP-signal recorder 123 with devices for amplifying and processing EP-signals received from the catheter port 121 , stimulation section 125 for feeding a cardiac stimulation signal to the catheter port 121 , and a module-microcontroller (MCU) 124 configured for controlling the operation of the EP-signal recorder 123 and the operation of the stimulation section 125. In this embodiment, a stimulation generator for generating the cardiac stimulation signal is integrated in the stimulation section 125 of the second catheter control module 120. The second catheter control module 120 communicates with the com- mon interface 130 through a galvanically isolated module interface port 126. The common interface 130 may further provide power to the second catheter control module 120 through a galvanically isolated module power supply 127.

The circuitry of the second catheter control module 120 further comprises an abla- tion section for supplying ablation energy to the EP-catheter port 121 of the second catheter control module 120. The ablation section 128 comprises an ablation control device 128a for coupling a common ablation source to the catheter port 121. In this embodiment, the common ablation source is a common ablation input port 140 configured for receiving ablation energy from an external ablation generator 40.

By this design, the first catheter control module 1 10 is galvanically isolated from the second catheter control module 120 (and any further catheter control modules). In the context of the EP-workstation, the first catheter control module 1 10 forms a first galvanic ensemble together with the associated EP-catheter 10 connected to cathe- ter port 1 1 1. Accordingly, the second catheter control module 120 forms a second galvanic ensemble together with the associated EP-catheter 20 connected to catheter port 121. The external ablation generator 40 preferably has a galvanically isolated power supply and, when connected to the catheter port 121 via the ablation con- trol device 128a, forms a galvanic ensemble with the second catheter control module 120 and the EP-catheter 20 associated therewith. The first and second galvanic ensembles are isolated from each other. A resistive connection between the two galvanic ensembles may thus only occur through the patient when operated together in a multiple catheter procedure. Thereby common mode noise and inter-catheter interferences are efficiently suppressed.

The modular control unit 100 is adapted for use in an EP-workstation for performing multiple catheter cardiac electrophysiology procedures on a patient. The EP- workstation is represented by a first EP-catheter 10 connected to the catheter port 1 1 1 of the first catheter control module 1 10, a second EP-catheter 20 connected to the catheter port 121 of the second catheter control module 120, a central computer system 30 communicating with the modular control unit 100 through a computer interface port 131 of the common interface 130, and external devices 40, 50, 60. The circuitry of the galvanically isolated catheter control modules 1 10, 120 may further comprise additional components 1 19, 129 that are equally controlled by the respective module microcontrollers 1 13, 123 and that may require galvanic connection to the EP-catheters 10, 20, such as measuring devices for 3D-localisation and positioning of the distal ends of the EP-catheters 10, 20.

The block diagram in FIG. 3 shows schematically the architecture of a modular control unit 200 for use in a cardiac EP-workstation according to a further embodiment of the invention. The modular control unit 200 of Fig. 3 corresponds to the modular control unit 100 of Fig. 2, wherein corresponding reference numerals refer to corre- sponding elements. The modular control unit 200 of Fig. 3 differs from the modular control unit 100 of Fig. 2 in the layout of the stimulation sections. In the embodiment of Fig. 3, the stimulation sections 215, 225 of the first and second control modules 210, 220 comprise switching devices 215a, 225a for coupling a common stimulation source to the respective catheter ports 21 1 , 221 . The common stimulation source is a common stimulation input port 170 of the modular control unit 200, which is configured for receiving a stimulation signal from an external stimulation generator 70.

The common stimulation input port 170 is connected to a stimulation input of the switching device 215a of the first catheter control module 210, and to a stimulation input of the switching device 225a of the second catheter control module 220. The switching devices 215a, 225a are controlled by the respective module microcontrollers 214, 224. In an 'OFF-state' the switching device 215a galvanically separates the common stimulation input port 70 from the catheter port 21 1 of the first catheter control module 210. Accordingly when switched OFF, the switching device 225a galvanically separates the common stimulation input port 70 from the catheter port 221 of the second catheter control module 220. In an 'ON-state', the switching devices 215a, 225a establish a galvanic connection between the respective catheter port 21 1 , 221 and the common stimulation input port 70. To maintain galvanic isola- tion between the first and second catheter control modules 210, 220 under operation, the switching of all switching devices 215a, 225a may be coordinated through the common interface 230 so as to only switch ON the switching device 215a of the first catheter control module 210 when the switching device 225a of the second catheter control module 220 is switched OFF, and vice versa.

FIG. 4 shows a schematic view of an embodiment of a modular control unit with reference relay means 380. A first catheter 10A is connected to a first catheter control module 31 OA, here symbolized by an amplifier and an A D-converter, via electrode lines A1 , A2. The electrode lines A1 , A2 each connect an electrode on the distal portion of a respective EP-catheter 10A with the circuitry 31 OA of the first catheter control module. In the embodiment of Fig. 4 the EP-catheters are connected with two electrode lines A1 , A2 wherein one electrode line A1 , the reference electrode line, is connected to the reference input of the amplifier ("-"), and a further electrode line A2, the probe electrode line, is connected to the signal input ("+") of the amplifi- er. While only two electrode lines are shown, it should be noted that the number of electrode lines may generally vary depending on the number of available electrodes on a given EP-catheter and on the EP-procedures to be performed. In the same manner as the first catheter 10A, second and third catheters 10B, 10C are connect- ed to respective catheter control modules 310B, 310C, wherein electrode lines A1 , B1 , C1 are reference electrode lines as described above.

The relay means 380 has a common line 381 and switches 380A, 380B, 380C, 380R. A first switch 380A is adapted to electrically connect the electrode line A1 of the first catheter control module to the common line 381 . Accordingly, second and third switches 380B, 380C are adapted to electrically connect electrode lines B1 , C1 of respective second and third catheter control modules to the common line 381. A further switch 380R, the reference switch, is adapted to electrically connect an ex- ternal reference line to the common line, said external reference line being connected to an external reference 80 such as a reference generated from a Wilson Central Terminal (WCT) arrangement of electrodes 81 . Advantageously, the electrodes of the WCT-arrangement are a plurality of resistively coupled body surface electrodes 81 for attachment to the patient.

When all switches 380A, 380B, 380C, 380R are open ( FF'-state), the catheter control modules, the common line 381 , and the external reference are galvanically isolated from each other and may each float at a respective reference potential P1 , P2, P3, P4, P5. By closing the first switch 380A (ΌΝ'-state), the first reference po- tential P1 of the first catheter control module is clamped to the common potential P5 of the common line. By further closing the reference switch 380R, the potentials P1 and P5 are clamped to the external reference potential P4 of the external reference 80 and signals probed by the first catheter 10A via signal electrode line A2 are thus referred to the external reference of the WCT-arrangement of electrodes 80. By fur- ther closing switch 380B, the second reference potential P2 of the second catheter control module is clamped to the common potential P5 and, keeping the reference switch 380R closed, to the external reference potential P4. When both the first and the second switches 380A, 380B are closed, the reference electrode lines of the first and second catheter control modules are electrically connected. The first and sec- ond catheter control modules are thus grouped together as a galvanic entity floating at a common reference potential P1 , P2, P5, which may optionally be clamped to an external reference potential P4. Signals probed by different electrodes on the first and second catheters and transmitted via the signal electrode lines A2, B2 to the first and second catheter control modules may thus be referred to each other. As long as the third switch 380C remains open, the galvanic entity formed by the first and second catheter control modules is still galvanically isolated from the third catheter control module, which floats at its own reference potential P3. However, as shown in Fig. 4, the relay means may even allow for fully lifting the galvanic isolation between catheter control modules by also closing switch 380C. Thereby, a fully versatile EP-workstation may be provided allowing for freely and selectively referring signals from multiple electrodes of separate catheters to each other or keeping the probed signals apart from each other as desired. The embodiment shown schematically in FIG. 5 corresponds to the embodiment of Fig. 4 with the addition of an external/common stimulation source 70 that may be selectively coupled to the different catheter control modules by means of cooperating stimulation relays 470, 490. The stimulation relays 470, 490 each have common lines 471 , 491 and switches 470A-C, 490A-C that are each adapted to electrically connect an electrode line to the respective common lines. A stimulation reference terminal 71 is coupled to the common line 491 of the stimulation reference relay 490, and a stimulation signal terminal 72 is coupled to the common line 471 of the stimulation signal relay 470. The common line 471 of the stimulation signal relay 470 has potential P6, and the common line 491 of the stimulation reference relay 490 has potential P7. In an ΌΝ'-state, the stimulation signal switches 470A, 470B,-470C electrically connect the respective signal electrode lines A2, B2, C2 via the common line 471 to the stimulation signal terminal 72 of the stimulation source 70, and the corresponding stimulation reference switches 490A, 490B, 490C electrically connect the respective reference electrode lines A1 , B1 , C1 via the common line 491 to the stimulation reference terminal 71 . The switches 470A-C of the stimulation signal relay 470 and the switches 490A-C of the stimulation reference relay are operated pairwise to couple the stimulation source to a given EP-catheter and apply the EP- stimulus between a reference electrode and a signal electrode of the given EP- catheter. Preferably, the operation of the stimulation signal switches 470A-C is co- ordinated with the operation of the stimulation reference switches so as to only couple the stimulation signal to one catheter at a time. The stimulation reference potential P7 may be clamped to an external reference potential P4 by closing a reference switch 490R connecting the common line 491 of the stimulation reference relay 490 to the external reference 80, such as a WCT-arrangement of electrodes 81. Prefer- ably, the stimulation source 70 is 'soft-coupled' to the respective EP-catheter to avoid any disturbances arising from a sudden change in potential that may be leveraged by the capacitance of the floating metallic elements to be coupled together. This may be achieved by appropriate electric filtering. An example for such filtering applied to the coupling circuitry is shown in Fig. 6 by way of example. The filter of Fig. 6 is an R-C-filter acting as a low-pass filter for the stimulation signal so as to suppress rapidly changing transient signal components that may give rise to unde- sired artefacts. For example, resistor R and capacitor C may be chosen such that the low-pass filter has a cut-off frequency of about 30 Hz.

REFERENCE NUMERALS

1 EP-workstation

2 modular control unit

3 catheter control port

4 computer

5, 6, 7, 8 user interface and display means

10, 10A-C, 20 EP-catheter

11 distal portion

12 distal end

13 proximal portion

14 handle

15 cable

16 stimulation generator

30 computer

40 ablation generator

50, 60 user interface and display means 70 stimulation generator

100, 200 modular control unit

110, 120,210,220 catheter control module

111, 112, 211, 212 catheter port

112, 122, 212, 222 defibrillation protection

113, 123, 213, 223 EP-recorder

114, 124, 214, 224 module microcontroller

115, 125,215,225 stimulation section

215a, 225a switching device

116, 126, 216, 226 module interface port

117, 127, 217, 227 module power supply

128, 228 ablation section

128a, 228a ablation control device

119, 129, 219, 229 additional devices

130, 230 common interface

131, 231 computer interface port

140 ablation input port 170 stimulation input port

10A-C EP-catheter

80 external reference

81 body surface electrodes

310A-C, 410A-C catheter control module circuitry

380, 470, 480, 490 relay

380A-C, 470A-C, 480A-C, 490A-C electrode switches 380R, 480R, 490R reference switches

381 , 471 , 481 , 491 common line

A1 , B1 , C1 , A2, B2, C2electrode lines

P1 -P7 potentials

Claims

Modular control unit for a multiple catheter cardiac electrophysiology (EP) system, the modular control unit comprising

- a common interface configured for communicating with a computer through a computer interface port,

- a first catheter control module configured for cardiac EP-diagnosis and

- a second catheter control module configured for cardiac EP-diagnosis, the first and second catheter control modules each having circuitry comprising a catheter port configured for electrically connecting one or more electrodes of an EP-catheter to the circuitry, an EP-signal recorder comprising devices for amplifying and processing EP-signals received from the catheter port, a stimulation section for feeding a cardiac stimulation signal to the catheter port, and a module-microcontroller (MCU) configured for controlling the operation of the EP- signal recorder and the operation of the stimulation section, wherein the first and second catheter control modules are galvanically isolated from each other and wherein the first and second catheter control modules each communicate with the common interface through a respective, galvanically isolated module interface port.

Modular control unit according to claim 1 , wherein the stimulation section of one or more catheter control modules comprises a switching device for coupling a common stimulation source to the catheter port.

3. Modular control unit according to claim 2, wherein the switching of all switching devices is coordinated through the common interface so as to only couple the common stimulation source to the catheter port of one module at a time while keeping the catheter ports of all remaining modules decoupled.

4. Modular control unit according to claim 2 or claim 3, wherein the common stimulation source is a common stimulation generator provided within the modular unit.

5. Modular control unit according to claim 2 or claim 3, wherein the common stimulation source is a common stimulation input port configured for receiving a stimulation signal from an external stimulation generator.

6. Modular control unit according to claim 1 , wherein the stimulation section of at least two catheter control modules each comprises a stimulation generator.

7. Modular control unit according to any of the preceding claims, wherein at least one of the modules comprises an ablation section for supplying ablation energy to the EP-catheter port.

8. Modular control unit according to claim 7, wherein the ablation section comprises an ablation control device for coupling a common ablation source to the catheter port.

9. Modular control unit according to claim 8, wherein the common ablation source is a common ablation input port configured for receiving ablation energy from an external ablation generator.

10. Modular control unit according to any of the preceding claims, further comprising relay means, said relay means having a common line and at least a first switch, said first switch being adapted to electrically connect an electrode line of a first catheter control module to the common line.

1 1. Modular control unit according to claim 10, wherein the relay means further comprise at least a second switch, said second switch being adapted to electri- cally connect an electrode line of a second catheter control module to the common line.

12. Modular control unit according to claim 10 or claim 1 1 , wherein the relay means further comprises a reference switch, said reference switch being adapted to electrically connect an external reference line to the common line.

13. Modular control unit according to any one of claims 10-12, wherein the electrode lines are reference electrode lines.

14. Cardiac electrophysiology (EP) workstation comprising a modular control unit according to any of the preceding claims, the EP-workstation further comprising a central computer system communicating with the modular control unit through the computer interface port of the common interface.

15. Cardiac EP-workstation according to claim 14, further comprising a first EP- catheter connected to the catheter port of the first catheter control module, and a second EP-catheter connected to the catheter port of the second catheter control module.

16. Cardiac EP-workstation according to claim 14 or claim 15, wherein said central computer system is further configured for controlling external devices, said external devices comprising devices selected from the group of display devices, user interfaces, external stimulation generators, external ablation generators, medical imaging equipment, catheter navigation and positioning instrumentation, patient monitoring equipment, and patient data storage.