Multiple monophasic shocks improve electrotherapy of ventricular tachycardia in a rabbit model of chronic infarction

Wenwen Li, Crystal M Ripplinger, Qing Lou, Igor R. Efimov

Research output: Contribution to journalArticle

39 Citations (Scopus)

Abstract

Background: We previously showed that the cardioversion threshold (CVT) for ventricular tachycardia (VT) is phase dependent when a single monophasic shock (1MP) is used. Objective: The purpose of this study was to extend these findings to a biphasic shock (1BP) and to compare the efficacy of phase-independent multiple monophasic (5MP) and biphasic shocks (5BP). Methods: Panoramic optical mapping with blebbistatin (5 μM) was performed in postmyocardial infarction rabbit hearts (n = 8). Flecainide (1.64 ± 0.68 μM) was administered to promote sustained arrhythmias. 5MP and 5BP were applied within one VT cycle length (CL). Results were compared to 1BP and antitachycardia pacing. Results: We observed monomorphic VT with CL = 149.6 ± 18.0 ms. Similar to 1MP, CVTs of 1BP were found to be phase dependent, and the maximum versus minimum CVT was 8.6 ± 1.7 V/cm versus 3.7 ± 1.9 V/cm, respectively (P = .0013). Efficacy of 5MP was higher than that of 1BP and 5BP. CVT was 3.2 ± 1.4 V/cm for 5MP versus 5.3 ± 1.9 V/cm for 5BP (P = .00027). 5MP versus averaged 1BP CVT was 3.6 ± 2.1 V/cm versus. 6.8 ± 1.5 V/cm, respectively (P = .00024). Antitachycardia pacing was found to be completely ineffective in this model. Conclusion: Maintenance of shock-induced virtual electrode polarization by multiple monophasic shocks over a VT cycle is responsible for unpinning of reentry leading to self-termination. Elimination of virtual electrode polarization by shock polarity reversal during multiple biphasic shocks proved ineffective. A significant reduction in CVT can be achieved by applying multiple monophasic shocks within one VT CL or one single shock at the proper coupling interval.

Original languageEnglish (US)
Pages (from-to)1020-1027
Number of pages8
JournalHeart Rhythm
Volume6
Issue number7
DOIs
StatePublished - Jul 2009
Externally publishedYes

Fingerprint

Electric Stimulation Therapy
Ventricular Tachycardia
Infarction
Shock
Rabbits
Electric Countershock
Electrodes
Flecainide
Cardiac Arrhythmias

Keywords

  • Cardioversion
  • Infarction
  • Optical mapping
  • Ventricular tachycardia

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

Cite this

Multiple monophasic shocks improve electrotherapy of ventricular tachycardia in a rabbit model of chronic infarction. / Li, Wenwen; Ripplinger, Crystal M; Lou, Qing; Efimov, Igor R.

In: Heart Rhythm, Vol. 6, No. 7, 07.2009, p. 1020-1027.

Research output: Contribution to journalArticle

@article{76adbefc98f343b49e8673dc14bfe114,
title = "Multiple monophasic shocks improve electrotherapy of ventricular tachycardia in a rabbit model of chronic infarction",
abstract = "Background: We previously showed that the cardioversion threshold (CVT) for ventricular tachycardia (VT) is phase dependent when a single monophasic shock (1MP) is used. Objective: The purpose of this study was to extend these findings to a biphasic shock (1BP) and to compare the efficacy of phase-independent multiple monophasic (5MP) and biphasic shocks (5BP). Methods: Panoramic optical mapping with blebbistatin (5 μM) was performed in postmyocardial infarction rabbit hearts (n = 8). Flecainide (1.64 ± 0.68 μM) was administered to promote sustained arrhythmias. 5MP and 5BP were applied within one VT cycle length (CL). Results were compared to 1BP and antitachycardia pacing. Results: We observed monomorphic VT with CL = 149.6 ± 18.0 ms. Similar to 1MP, CVTs of 1BP were found to be phase dependent, and the maximum versus minimum CVT was 8.6 ± 1.7 V/cm versus 3.7 ± 1.9 V/cm, respectively (P = .0013). Efficacy of 5MP was higher than that of 1BP and 5BP. CVT was 3.2 ± 1.4 V/cm for 5MP versus 5.3 ± 1.9 V/cm for 5BP (P = .00027). 5MP versus averaged 1BP CVT was 3.6 ± 2.1 V/cm versus. 6.8 ± 1.5 V/cm, respectively (P = .00024). Antitachycardia pacing was found to be completely ineffective in this model. Conclusion: Maintenance of shock-induced virtual electrode polarization by multiple monophasic shocks over a VT cycle is responsible for unpinning of reentry leading to self-termination. Elimination of virtual electrode polarization by shock polarity reversal during multiple biphasic shocks proved ineffective. A significant reduction in CVT can be achieved by applying multiple monophasic shocks within one VT CL or one single shock at the proper coupling interval.",
keywords = "Cardioversion, Infarction, Optical mapping, Ventricular tachycardia",
author = "Wenwen Li and Ripplinger, {Crystal M} and Qing Lou and Efimov, {Igor R.}",
year = "2009",
month = "7",
doi = "10.1016/j.hrthm.2009.03.015",
language = "English (US)",
volume = "6",
pages = "1020--1027",
journal = "Heart Rhythm",
issn = "1547-5271",
publisher = "Elsevier",
number = "7",

}

TY - JOUR

T1 - Multiple monophasic shocks improve electrotherapy of ventricular tachycardia in a rabbit model of chronic infarction

AU - Li, Wenwen

AU - Ripplinger, Crystal M

AU - Lou, Qing

AU - Efimov, Igor R.

PY - 2009/7

Y1 - 2009/7

N2 - Background: We previously showed that the cardioversion threshold (CVT) for ventricular tachycardia (VT) is phase dependent when a single monophasic shock (1MP) is used. Objective: The purpose of this study was to extend these findings to a biphasic shock (1BP) and to compare the efficacy of phase-independent multiple monophasic (5MP) and biphasic shocks (5BP). Methods: Panoramic optical mapping with blebbistatin (5 μM) was performed in postmyocardial infarction rabbit hearts (n = 8). Flecainide (1.64 ± 0.68 μM) was administered to promote sustained arrhythmias. 5MP and 5BP were applied within one VT cycle length (CL). Results were compared to 1BP and antitachycardia pacing. Results: We observed monomorphic VT with CL = 149.6 ± 18.0 ms. Similar to 1MP, CVTs of 1BP were found to be phase dependent, and the maximum versus minimum CVT was 8.6 ± 1.7 V/cm versus 3.7 ± 1.9 V/cm, respectively (P = .0013). Efficacy of 5MP was higher than that of 1BP and 5BP. CVT was 3.2 ± 1.4 V/cm for 5MP versus 5.3 ± 1.9 V/cm for 5BP (P = .00027). 5MP versus averaged 1BP CVT was 3.6 ± 2.1 V/cm versus. 6.8 ± 1.5 V/cm, respectively (P = .00024). Antitachycardia pacing was found to be completely ineffective in this model. Conclusion: Maintenance of shock-induced virtual electrode polarization by multiple monophasic shocks over a VT cycle is responsible for unpinning of reentry leading to self-termination. Elimination of virtual electrode polarization by shock polarity reversal during multiple biphasic shocks proved ineffective. A significant reduction in CVT can be achieved by applying multiple monophasic shocks within one VT CL or one single shock at the proper coupling interval.

AB - Background: We previously showed that the cardioversion threshold (CVT) for ventricular tachycardia (VT) is phase dependent when a single monophasic shock (1MP) is used. Objective: The purpose of this study was to extend these findings to a biphasic shock (1BP) and to compare the efficacy of phase-independent multiple monophasic (5MP) and biphasic shocks (5BP). Methods: Panoramic optical mapping with blebbistatin (5 μM) was performed in postmyocardial infarction rabbit hearts (n = 8). Flecainide (1.64 ± 0.68 μM) was administered to promote sustained arrhythmias. 5MP and 5BP were applied within one VT cycle length (CL). Results were compared to 1BP and antitachycardia pacing. Results: We observed monomorphic VT with CL = 149.6 ± 18.0 ms. Similar to 1MP, CVTs of 1BP were found to be phase dependent, and the maximum versus minimum CVT was 8.6 ± 1.7 V/cm versus 3.7 ± 1.9 V/cm, respectively (P = .0013). Efficacy of 5MP was higher than that of 1BP and 5BP. CVT was 3.2 ± 1.4 V/cm for 5MP versus 5.3 ± 1.9 V/cm for 5BP (P = .00027). 5MP versus averaged 1BP CVT was 3.6 ± 2.1 V/cm versus. 6.8 ± 1.5 V/cm, respectively (P = .00024). Antitachycardia pacing was found to be completely ineffective in this model. Conclusion: Maintenance of shock-induced virtual electrode polarization by multiple monophasic shocks over a VT cycle is responsible for unpinning of reentry leading to self-termination. Elimination of virtual electrode polarization by shock polarity reversal during multiple biphasic shocks proved ineffective. A significant reduction in CVT can be achieved by applying multiple monophasic shocks within one VT CL or one single shock at the proper coupling interval.

KW - Cardioversion

KW - Infarction

KW - Optical mapping

KW - Ventricular tachycardia

UR - http://www.scopus.com/inward/record.url?scp=67549089543&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=67549089543&partnerID=8YFLogxK

U2 - 10.1016/j.hrthm.2009.03.015

DO - 10.1016/j.hrthm.2009.03.015

M3 - Article

C2 - 19560090

AN - SCOPUS:67549089543

VL - 6

SP - 1020

EP - 1027

JO - Heart Rhythm

JF - Heart Rhythm

SN - 1547-5271

IS - 7

ER -