Complex excitation dynamics underlie polymorphic ventricular tachycardia in a transgenic rabbit model of long QT syndrome type 1

Tae Yun Kim, Yukiko Kunitomo, Zachary Pfeiffer, Divyang Patel, Jungmin Hwang, Kathryn Harrison, Brijesh Patel, Paul Jeng, Ohad Ziv, Yichun Lu, Xuwen Peng, Zhilin Qu, Gideon Koren, Bum Rak Choi

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

BACKGROUND: Long QT syndrome type 1 (LQT1) is a congenital disease arising from a loss of function in the slowly activating delayed potassium current IKs, which causes early afterdepolarizations (EADs) and polymorphic ventricular tachycardia (pVT). OBJECTIVE The purpose of this study was to investigate the mechanisms underlying pVT using a transgenic rabbit model of LQT1. METHODS: Hearts were perfused retrogradely, and action potentials were recorded using a voltage-sensitive dye and CMOS cameras. RESULTS: Bolus injection of isoproterenol (140 nM) induced pVT initiated by focal excitations from the right ventricle (RV; n = 16 of 18 pVTs). After the pVT was initiated, complex focal excitations occurred in both the RV and the left ventricle, which caused oscillations of the QRS complexes on ECG, consistent with the recent proposal of multiple shifting foci caused by EAD chaos. Moreover, the action potential upstroke in pVT showed a bimodal distribution, demonstrating the coexistence of 2 types of excitation that interacted to produce complex pVT: Na+ current (INa)-mediated fast conduction and L-type Ca2+ current (ICa)-mediated slow conduction coexist, manifesting as pVT. Addition of 2 μM tetrodotoxin to reduce INa converted pVT into monomorphic VT. Reducing late INa in computer simulation converted pVT into a single dominant reentry, agreeing with experimental results. CONCLUSION :Our study demonstrates that pVT in LQT1 rabbits is initiated by focal excitations from the RV and is maintained by multiple shifting foci in both ventricles. Moreover, wave conduction in pVT exhibits bi-excitability, that is, fast wavefronts driven by INa and slow wavefronts driven by ICa co-exist during pVT.

Original languageEnglish (US)
Pages (from-to)220-228
Number of pages9
JournalHeart Rhythm
Volume12
Issue number1
DOIs
StatePublished - Jan 1 2015

Fingerprint

Romano-Ward Syndrome
Ventricular Tachycardia
Rabbits
Action Potentials
Heart Ventricles
Tetrodotoxin
Isoproterenol

All Science Journal Classification (ASJC) codes

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

Cite this

Kim, Tae Yun ; Kunitomo, Yukiko ; Pfeiffer, Zachary ; Patel, Divyang ; Hwang, Jungmin ; Harrison, Kathryn ; Patel, Brijesh ; Jeng, Paul ; Ziv, Ohad ; Lu, Yichun ; Peng, Xuwen ; Qu, Zhilin ; Koren, Gideon ; Choi, Bum Rak. / Complex excitation dynamics underlie polymorphic ventricular tachycardia in a transgenic rabbit model of long QT syndrome type 1. In: Heart Rhythm. 2015 ; Vol. 12, No. 1. pp. 220-228.
@article{a8d4cd1e933b48029273d743e0a28d34,
title = "Complex excitation dynamics underlie polymorphic ventricular tachycardia in a transgenic rabbit model of long QT syndrome type 1",
abstract = "BACKGROUND: Long QT syndrome type 1 (LQT1) is a congenital disease arising from a loss of function in the slowly activating delayed potassium current IKs, which causes early afterdepolarizations (EADs) and polymorphic ventricular tachycardia (pVT). OBJECTIVE The purpose of this study was to investigate the mechanisms underlying pVT using a transgenic rabbit model of LQT1. METHODS: Hearts were perfused retrogradely, and action potentials were recorded using a voltage-sensitive dye and CMOS cameras. RESULTS: Bolus injection of isoproterenol (140 nM) induced pVT initiated by focal excitations from the right ventricle (RV; n = 16 of 18 pVTs). After the pVT was initiated, complex focal excitations occurred in both the RV and the left ventricle, which caused oscillations of the QRS complexes on ECG, consistent with the recent proposal of multiple shifting foci caused by EAD chaos. Moreover, the action potential upstroke in pVT showed a bimodal distribution, demonstrating the coexistence of 2 types of excitation that interacted to produce complex pVT: Na+ current (INa)-mediated fast conduction and L-type Ca2+ current (ICa)-mediated slow conduction coexist, manifesting as pVT. Addition of 2 μM tetrodotoxin to reduce INa converted pVT into monomorphic VT. Reducing late INa in computer simulation converted pVT into a single dominant reentry, agreeing with experimental results. CONCLUSION :Our study demonstrates that pVT in LQT1 rabbits is initiated by focal excitations from the RV and is maintained by multiple shifting foci in both ventricles. Moreover, wave conduction in pVT exhibits bi-excitability, that is, fast wavefronts driven by INa and slow wavefronts driven by ICa co-exist during pVT.",
author = "Kim, {Tae Yun} and Yukiko Kunitomo and Zachary Pfeiffer and Divyang Patel and Jungmin Hwang and Kathryn Harrison and Brijesh Patel and Paul Jeng and Ohad Ziv and Yichun Lu and Xuwen Peng and Zhilin Qu and Gideon Koren and Choi, {Bum Rak}",
year = "2015",
month = "1",
day = "1",
doi = "10.1016/j.hrthm.2014.10.003",
language = "English (US)",
volume = "12",
pages = "220--228",
journal = "Heart Rhythm",
issn = "1547-5271",
publisher = "Elsevier",
number = "1",

}

Kim, TY, Kunitomo, Y, Pfeiffer, Z, Patel, D, Hwang, J, Harrison, K, Patel, B, Jeng, P, Ziv, O, Lu, Y, Peng, X, Qu, Z, Koren, G & Choi, BR 2015, 'Complex excitation dynamics underlie polymorphic ventricular tachycardia in a transgenic rabbit model of long QT syndrome type 1', Heart Rhythm, vol. 12, no. 1, pp. 220-228. https://doi.org/10.1016/j.hrthm.2014.10.003

Complex excitation dynamics underlie polymorphic ventricular tachycardia in a transgenic rabbit model of long QT syndrome type 1. / Kim, Tae Yun; Kunitomo, Yukiko; Pfeiffer, Zachary; Patel, Divyang; Hwang, Jungmin; Harrison, Kathryn; Patel, Brijesh; Jeng, Paul; Ziv, Ohad; Lu, Yichun; Peng, Xuwen; Qu, Zhilin; Koren, Gideon; Choi, Bum Rak.

In: Heart Rhythm, Vol. 12, No. 1, 01.01.2015, p. 220-228.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Complex excitation dynamics underlie polymorphic ventricular tachycardia in a transgenic rabbit model of long QT syndrome type 1

AU - Kim, Tae Yun

AU - Kunitomo, Yukiko

AU - Pfeiffer, Zachary

AU - Patel, Divyang

AU - Hwang, Jungmin

AU - Harrison, Kathryn

AU - Patel, Brijesh

AU - Jeng, Paul

AU - Ziv, Ohad

AU - Lu, Yichun

AU - Peng, Xuwen

AU - Qu, Zhilin

AU - Koren, Gideon

AU - Choi, Bum Rak

PY - 2015/1/1

Y1 - 2015/1/1

N2 - BACKGROUND: Long QT syndrome type 1 (LQT1) is a congenital disease arising from a loss of function in the slowly activating delayed potassium current IKs, which causes early afterdepolarizations (EADs) and polymorphic ventricular tachycardia (pVT). OBJECTIVE The purpose of this study was to investigate the mechanisms underlying pVT using a transgenic rabbit model of LQT1. METHODS: Hearts were perfused retrogradely, and action potentials were recorded using a voltage-sensitive dye and CMOS cameras. RESULTS: Bolus injection of isoproterenol (140 nM) induced pVT initiated by focal excitations from the right ventricle (RV; n = 16 of 18 pVTs). After the pVT was initiated, complex focal excitations occurred in both the RV and the left ventricle, which caused oscillations of the QRS complexes on ECG, consistent with the recent proposal of multiple shifting foci caused by EAD chaos. Moreover, the action potential upstroke in pVT showed a bimodal distribution, demonstrating the coexistence of 2 types of excitation that interacted to produce complex pVT: Na+ current (INa)-mediated fast conduction and L-type Ca2+ current (ICa)-mediated slow conduction coexist, manifesting as pVT. Addition of 2 μM tetrodotoxin to reduce INa converted pVT into monomorphic VT. Reducing late INa in computer simulation converted pVT into a single dominant reentry, agreeing with experimental results. CONCLUSION :Our study demonstrates that pVT in LQT1 rabbits is initiated by focal excitations from the RV and is maintained by multiple shifting foci in both ventricles. Moreover, wave conduction in pVT exhibits bi-excitability, that is, fast wavefronts driven by INa and slow wavefronts driven by ICa co-exist during pVT.

AB - BACKGROUND: Long QT syndrome type 1 (LQT1) is a congenital disease arising from a loss of function in the slowly activating delayed potassium current IKs, which causes early afterdepolarizations (EADs) and polymorphic ventricular tachycardia (pVT). OBJECTIVE The purpose of this study was to investigate the mechanisms underlying pVT using a transgenic rabbit model of LQT1. METHODS: Hearts were perfused retrogradely, and action potentials were recorded using a voltage-sensitive dye and CMOS cameras. RESULTS: Bolus injection of isoproterenol (140 nM) induced pVT initiated by focal excitations from the right ventricle (RV; n = 16 of 18 pVTs). After the pVT was initiated, complex focal excitations occurred in both the RV and the left ventricle, which caused oscillations of the QRS complexes on ECG, consistent with the recent proposal of multiple shifting foci caused by EAD chaos. Moreover, the action potential upstroke in pVT showed a bimodal distribution, demonstrating the coexistence of 2 types of excitation that interacted to produce complex pVT: Na+ current (INa)-mediated fast conduction and L-type Ca2+ current (ICa)-mediated slow conduction coexist, manifesting as pVT. Addition of 2 μM tetrodotoxin to reduce INa converted pVT into monomorphic VT. Reducing late INa in computer simulation converted pVT into a single dominant reentry, agreeing with experimental results. CONCLUSION :Our study demonstrates that pVT in LQT1 rabbits is initiated by focal excitations from the RV and is maintained by multiple shifting foci in both ventricles. Moreover, wave conduction in pVT exhibits bi-excitability, that is, fast wavefronts driven by INa and slow wavefronts driven by ICa co-exist during pVT.

UR - http://www.scopus.com/inward/record.url?scp=84920699979&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84920699979&partnerID=8YFLogxK

U2 - 10.1016/j.hrthm.2014.10.003

DO - 10.1016/j.hrthm.2014.10.003

M3 - Article

C2 - 25285647

AN - SCOPUS:84920699979

VL - 12

SP - 220

EP - 228

JO - Heart Rhythm

JF - Heart Rhythm

SN - 1547-5271

IS - 1

ER -