Cardiac Bioelectric Therapy: Mechanisms and Practical Implications

637 Pages·2008·18.36 MB·English

by  Igor R. Efimov

BOOK SNW001-Efimov (TypesetbySPi,Delhi) iof635 October10,2008 17:33
Cardiac Bioelectric Therapy
Mechanisms and Practical Implications
BOOK SNW001-Efimov (TypesetbySPi,Delhi) iiiof635 October10,2008 17:33
Cardiac Bioelectric Therapy
Mechanisms and Practical Implications
Editedby
Igor R. Efimov, PhD
Washington University
St. Louis, MO
Mark W. Kroll, PhD
California Polytechnic University and
University of Minnesota
Minneapolis, MN
Patrick J. Tchou, MD
Cleveland Clinic Foundation
Cleveland, OH
Foreword byRaymondE.Ideker, MD,PhD
123
BOOK SNW001-Efimov (TypesetbySPi,Delhi) ivof635 October10,2008 17:33
IgorR.Efimov,Ph.D. MarkW.Kroll,Ph.D.
WashingtonUniversity CaliforniaPolytechnicUniversity
St.Louis,MO and
UniversityofMinnesota
Minneapolis,MN
PatrickJ.Tchou,M.D.
ClevelandClinicFoundation
Cleveland,OH
ISBN:978-0-387-79402-0 e-ISBN:978-0-387-79403-7
LibraryofCongressControlNumber:2008936096
(cid:2)c 2009SpringerScience+BusinessMedia,LLC.
Allrightsreserved.Thisworkmaynotbetranslatedorcopiedinwholeorinpartwithoutthewrittenpermissionofthe
publisher(SpringerScience+BusinessMedia,LLC.,233SpringStreet,NewYork,NY10013,USA),exceptforbrief
excerptsinconnectionwithreviewsorscholarlyanalysis.Useinconnectionwithanyformofinformationstorageand
retrieval,electronicadaptation,computersoftware,orbysimilarordissimilarmethodologynowknownorhereafter
developedisforbidden.
Theuseinthispublicationoftradenames,trademarks,servicemarksandsimilarterms,eveniftheyarenotidentified
assuch,isnottobetakenasanexpressionofopinionastowhetherornottheyaresubjecttoproprietaryrights.
Whiletheadviceandinformationinthisbookarebelievedtobetrueandaccurateatthedateofgoingtopress,neither
theauthorsnortheeditorsnorthepublishercanacceptanylegalresponsibilityforanyerrorsoromissionsthatmay
bemade.Thepublishermakesnowarranty,expressorimplied,withrespecttothematerialcontainedherein.
Printedonacid-freepaper
9 8 7 6 5 4 3 2 1
springer.com
BOOK SNW001-Efimov (TypesetbySPi,Delhi) vof635 October10,2008 17:33
Contents
Preface xv
List of Contributors xix
Foreword xxiii
Part I History
1.1History of Cardiac Pacing 3
Earl Bakken: One Version of the First Pacemaker Story......................................................3
The Long List of Inventions and Observations that Led to the Pacemaker.....................4
Pulse Theory and Observations that Bradycardia Leads to Syncope........................4
Early Cardiac Pacing....................................................................................................................5
Internal Pacemakers......................................................................................................................6
Pacing for Nonsurgeons.........................................................................................................7
Power Innovations..................................................................................................................8
Programming...........................................................................................................................8
Dual-Chamber Pacing............................................................................................................9
Activity Rate Responders...................................................................................................10
Implantable Cardiac Defibrillators...................................................................................10
Michel Mirowski....................................................................................................................10
Conclusion.....................................................................................................................................12
References......................................................................................................................................12
1.2History of Defibrillation 15
Introduction: Defibrillation and Its Creators.........................................................................15
Mysteries of Early Research: Abdilgaard’s Chickens and Kite’s Successes....................17
Elucidating the Mechanism, Imagining the Cure.................................................................22
Defibrillation: From Russia and the Soviet Block................................................................26
Defibrillation: AC to DC, in America and Beyond..............................................................30
Conclusion.....................................................................................................................................35
References......................................................................................................................................38
v
BOOK SNW001-Efimov (TypesetbySPi,Delhi) viof635 October10,2008 17:33
vi Contents
1.3Ventricular Fibrillation: A Historical Perspective 41
Introduction..................................................................................................................................41
Concepts, Instruments, and Institutions: Nineteenth-Century Legacy............................42
The Clinic and the Laboratory.................................................................................................44
Ventricular Fibrillation: Experimental Evidence and Basic Concepts,
1880s–1920s...................................................................................................................................47
From Wiggers to Moe: The Multiple Wavelet Hypothesis.................................................52
Modern Concepts of Ventricular Fibrillation.........................................................................53
Concluding Remarks...................................................................................................................54
References and Notes..................................................................................................................54
Part II Theory of Electric Stimulation
and Defibrillation
2.1The Bidomain Theory of Pacing 63
Introduction..................................................................................................................................63
Unipolar Stimulation...................................................................................................................63
Make and Break Excitation.......................................................................................................64
Strength-Interval Curves............................................................................................................71
No-Response Phenomenon.........................................................................................................76
Effect of Potassium on Pacing..................................................................................................78
Time Dependence of the Anodal and Cathodal Refractory Periods................................79
Conclusion.....................................................................................................................................81
Acknowledgments.........................................................................................................................81
References......................................................................................................................................81
2.2Bidomain Model of Defibrillation 85
Introduction..................................................................................................................................85
Advancements Leading to the Development of the Bidomain Model of
Defibrillation.................................................................................................................................86
Bidomain Equations and Numerical Approaches for Large-Scale Simulations
in Shock-Induced Arrhythmogenesis and Defibrillation......................................................87
Governing Equations............................................................................................................88
Computational Considerations..........................................................................................89
Numerical Schemes...............................................................................................................90
Linear Solvers........................................................................................................................91
Models of the Heart in Vulnerability and Defibrillation Studies.......................................94
Description of Myocardial Geometry and Fiber Architecture....................................94
Representation of Ionic Currents and Membrane Electroporation............................95
Shock Electrodes and Waveforms.....................................................................................95
Arrhythmia Induction with an Electric Shock and Defibrillation.....................................96
BOOK SNW001-Efimov (TypesetbySPi,Delhi) viiof635 October10,2008 17:33
Contents vii
Postshock Activity in the Ventricles........................................................................................97
VEP Induced by the Shock in the 3D Volume of the Ventricles...............................97
Postshock Activations in the 3D Volume of the Ventricles.........................................99
ULV and LLV......................................................................................................................100
Shock-Induced Phase Singularities and Filaments......................................................102
Induction of Arrhythmia with Biphasic Shocks...........................................................102
Conclusion...................................................................................................................................104
Acknowledgments.......................................................................................................................105
References....................................................................................................................................105
2.3The Generalized Activating Function 111
Introduction................................................................................................................................111
The Activating Function..........................................................................................................112
The Generalized Activating Function...................................................................................114
Examples......................................................................................................................................116
Discussion....................................................................................................................................124
Limitations...........................................................................................................................125
Validation.............................................................................................................................126
Conclusion...................................................................................................................................126
Appendix.....................................................................................................................................126
References....................................................................................................................................130
2.4Theory of Electroporation 133
Concept of Electroporation......................................................................................................133
Physical Background of Electroporation..............................................................................134
Pore Energy.........................................................................................................................134
Pore Creation......................................................................................................................136
Pore Evolution....................................................................................................................137
Postshock Pore Shrinkage and Coarsening...................................................................138
Pore Resealing.....................................................................................................................139
Mathematical Modeling of Electroporation.........................................................................140
Advection-Diffusion Equation..........................................................................................140
Asymptotic Model of Electroporation...........................................................................141
Current–Voltage Relationship of a Pore........................................................................142
Example of the Electroporation Process..............................................................................144
Governing Equation for the Transmembrane Potential.............................................144
Membrane Charging Phase..............................................................................................145
Pore Creation Phase..........................................................................................................145
Pore Evolution Phase........................................................................................................146
Postshock Pore Shrinkage Phase.....................................................................................148
Pore Resealing Phase.........................................................................................................149
Effects of Shock Strength.................................................................................................149
Limitations..................................................................................................................................151
BOOK SNW001-Efimov (TypesetbySPi,Delhi) viiiof635 October10,2008 17:33
viii Contents
Conclusion...................................................................................................................................153
Acknowledgment........................................................................................................................153
Appendix 1: Parameters of the Electroporation Model....................................................154
Appendix 2: Numerical Implementation...............................................................................155
References....................................................................................................................................156
Part III Electrode Mapping of Defibrillation
3.1Critical Points and the Upper Limit of Vulnerability for Defibrillation 165
Introduction................................................................................................................................165
Mechanisms by which Shocks Induce VF.............................................................................167
The Field-Recovery Critical Point.........................................................................................169
Inconsistencies with the Field-Recovery Critical Hypothesis for Defibrillation...........180
The Virtual Electrode Critical Point.....................................................................................182
Other Possible Mechanisms for Defibrillation.....................................................................185
Acknowledgment........................................................................................................................185
References....................................................................................................................................185
3.2The Role of Shock-Induced Nonregenerative Depolarizations 189
Brief Historical Perspectives....................................................................................................189
The Era of Computerized Cardiac Mapping: New Insights.............................................194
Initiation of VF by Electrical Stimuli............................................................................195
Different Proposed Hypotheses of Defibrillation.................................................................196
The Graded Response Hypothesis of Fibrillation and Defibrillation......................199
Graded Response Characteristics...................................................................................199
Conclusions and Future Directions........................................................................................211
Acknowledgment........................................................................................................................212
References....................................................................................................................................212
Part IV Optical Mapping of Stimulation
and Defibrillation
4.1Mechanisms of Isolated Cell Stimulation 221
Introduction................................................................................................................................221
Transmembrane Potential (Vm) Responses of an Isolated Cell....................................222
Theoretical Framework of Field Stimulation................................................................222
Experimental Responses During Field Stimulation....................................................225
Single Cells Versus Tissue Responses: Similarities and Differences........................236
Field-Induced Responses of an Isolated Cell-Pair: Sawtooth Effect...............................237
Theoretical Treatment of Sawtooth Effect....................................................................238
Experimental Measurement of Sawtooth Effect..........................................................239
Sawtooth Effect’s Role in Tissue: “Fact or Fantasy”.................................................241
BOOK SNW001-Efimov (TypesetbySPi,Delhi) ixof635 October10,2008 17:33
Contents ix
Effect of Electric Fields on Intracellular Calcium..............................................................243
2+
Measurement of Intracellular Ca Transients Using
Fluorescent Probes.............................................................................................................244
2+
Effect of Field Stimulation on Intracellular Ca Transients at Rest..................244
2+
Effect of Field Stimulation on Intracellular Ca Transients
During Plateau....................................................................................................................248
2+
Implications of Field-Induced Ca Gradients..........................................................248
Conclusion...................................................................................................................................249
References....................................................................................................................................249
4.2The Role of Microscopic Tissue Structure in Defibrillation 255
Introduction................................................................................................................................255
Possible Mechanisms of Intramural Shock-Induced Vm Changes.................................256
The Role of Microscopic Tissue Structure in the Shock Effects:
Experiments in Cell Cultures..................................................................................................258
The Role of Cell Boundaries in Shock Effects.............................................................259
The Role of Intercellular Clefts in the Shock Effects.................................................261
Shock-Induced ΔVm in Cell Strands...........................................................................263
Measurements of Intramural Shock-Induced ΔVm in
Wedge Preparations..................................................................................................................270
Comparison between Microscopic and Macroscopic
ΔVm Measurements................................................................................................................275
Conclusion...................................................................................................................................277
References....................................................................................................................................277
4.3Virtual Electrode Theory of Pacing 283
Introduction................................................................................................................................283
Virtual Electrodes during Unipolar Stimulation of Cardiac Tissue...............................284
Anode and Cathode Make and Break Excitation...............................................................290
Strength–Interval Curves.........................................................................................................293
Quatrefoil Reentry.....................................................................................................................296
Defibrillation...............................................................................................................................301
The No-Response Phenomenon and the Upper Limit of Vulnerability.........................306
Influence of Physical Electrodes During a Shock................................................................306
The Effect of Fiber Curvature on Stimulation of Cardiac Tissue...................................307
Heterogeneities...........................................................................................................................310
Averaging over Depth During Optical Mapping.................................................................311
Boundary Conditions and the Bidomain Model.................................................................312
The Magnetic Field Produced by Cardiac Tissue..............................................................313
Conclusion...................................................................................................................................315
Acknowledgments.......................................................................................................................316
References....................................................................................................................................317
BOOK SNW001-Efimov (TypesetbySPi,Delhi) xof635 October10,2008 17:33
x Contents
4.4The Virtual Electrode Hypothesis of Defibrillation 331
Introduction................................................................................................................................331
Historical Overview of Defibrillation Therapy.............................................................331
Bidomain Model.................................................................................................................332
Fluorescent Optical Mapping...........................................................................................333
Virtual Electrodes and the Activating Function.........................................................334
Mechanisms of Defibrillation...................................................................................................335
Theories of Defibrillation..................................................................................................335
Virtual Electrode Hypothesis of Defibrillation: The Role of
Deexcitation and Reexcitation........................................................................................336
Virtual Electrode-Induced Phase Singularity Mechanism.........................................337
ChiralityofShock-InducedReentryPredictedbyVEPNottheRepolarization
Gradient................................................................................................................................340
Shock-Induced VEP as a Mechanism for Defibrillation Failure...............................343
The Role of Electroporation....................................................................................................344
Clinical Implications of the Virtual Electrode Hypothesis of Defibrillation.................344
The Role of Virtual Electrodes and Shock Polarity...................................................344
Waveform Optimization....................................................................................................345
Toward Low-Energy Defibrillation.........................................................................................347
Conclusion...................................................................................................................................351
References....................................................................................................................................351
4.5Simultaneous Optical and Electrical Recordings 357
Introduction to Electrooptical Measurements.....................................................................357
ITO Properties...........................................................................................................................358
Ratiometric Optical Mapping.................................................................................................359
Role of the Second Spatial Derivative of the Extracellular Potential
in Field Stimulation...................................................................................................................360
Stimulatory Effects of a Spatial Variation of Extracellular Conductance
in an Electric Field....................................................................................................................364
Effect of Unipolar Stimulation in the Tissue under the Electrode.................................365
Electrooptical Mapping of Cardiac Excitation....................................................................368
Method of Electrooptical Mapping........................................................................................369
Electrooptical Mapping of Epicardially Paced Beats and Sinus Beats..........................370
Electrooptical Mapping of Fibrillation..................................................................................375
Conclusion...................................................................................................................................378
References....................................................................................................................................378
4.6Optical Mapping of Multisite Ventricular Fibrillation Synchronization 381
Pacing to Terminate Ventricular Fibrillation......................................................................382
New Opportunities in Improving Ventricular Defibrillation............................................382
Optical Mapping of Multisite Synchronization of Ventricular Fibrillation...................383
Optical Recording-Guided Pacing to Create Functional Block during VF...................387