Alternans in genetically modified Langendorff-perfused murine hearts modeling catecholaminergic polymorphic ventricular tachycardia

The relationship between alternans and arrhythmogenicity was studied in genetically modified murine hearts modeling catecholaminergic polymorphic ventricular tachycardia (CPVT) during Langendorff perfusion, before and after treatment with catecholamines and a β-adrenergic antagonist. Hetero...

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Main Authors: Ian N Sabir, Nan Ma, Victoria Jones, Catharine A Goddard, Yanmin Zhang, Asli Kalin, Andrew Grace, Christopher Huang
Format: Article
Language:English
Published: Frontiers Media S.A. 2010-10-01
Series:Frontiers in Physiology
Subjects:
Online Access:http://journal.frontiersin.org/Journal/10.3389/fphys.2010.00126/full
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author Ian N Sabir
Ian N Sabir
Nan Ma
Victoria Jones
Catharine A Goddard
Yanmin Zhang
Yanmin Zhang
Asli Kalin
Andrew Grace
Andrew Grace
Christopher Huang
Christopher Huang
author_facet Ian N Sabir
Ian N Sabir
Nan Ma
Victoria Jones
Catharine A Goddard
Yanmin Zhang
Yanmin Zhang
Asli Kalin
Andrew Grace
Andrew Grace
Christopher Huang
Christopher Huang
author_sort Ian N Sabir
collection DOAJ
description The relationship between alternans and arrhythmogenicity was studied in genetically modified murine hearts modeling catecholaminergic polymorphic ventricular tachycardia (CPVT) during Langendorff perfusion, before and after treatment with catecholamines and a β-adrenergic antagonist. Heterozygous (RyR2p/s) and homozygous (RyR2s/s) RyR2-P2328S hearts, and wild-type (WT) controls, were studied before and after treatment with epinephrine (100 nM and 1 µM) and propranolol (100 nM). Monophasic action potential recordings demonstrated significantly greater incidences of arrhythmia in RyR2s/p and RyR2s/s hearts as compared to WTs. Arrhythmogenicity in RyR2s/s hearts was associated with alternans, particularly at short baseline cycle lengths. Both phenomena were significantly accentuated by treatment with epinephrine and significantly diminished by treatment with propranolol, in full agreement with clinical expectations. These changes took place, however, despite an absence of changes in action potential durations, ventricular effective refractory periods or restitution curve characteristics. Furthermore pooled data from all hearts in which arrhythmia occurred demonstrated significantly greater alternans magnitudes, but similar restitution curve slopes, to hearts that did not demonstrate arrhythmia. These findings thus further validate the RyR2-P2328S murine heart as a model for human CPVT, confirming an alternans phenotype in common with murine genetic models of the Brugada syndrome and the congenital long-QT syndrome type 3. In contrast to these latter similarities, however, this report demonstrates the dissociation of alternans from changes in the properties of restitution curves for the first time in a murine model of a human arrhythmic syndrome.
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spelling doaj.art-517a276883b545069e7e23f085790d782022-12-21T23:58:23ZengFrontiers Media S.A.Frontiers in Physiology1664-042X2010-10-01110.3389/fphys.2010.001262112Alternans in genetically modified Langendorff-perfused murine hearts modeling catecholaminergic polymorphic ventricular tachycardiaIan N Sabir0Ian N Sabir1Nan Ma2Victoria Jones3Catharine A Goddard4Yanmin Zhang5Yanmin Zhang6Asli Kalin7Andrew Grace8Andrew Grace9Christopher Huang10Christopher Huang11University of CambridgeHammersmith HospitalJohn Radcliffe HospitalPapworth HospitalUniversity of CambridgeUniversity of CambridgeUniversity of CambridgeJohn Radcliffe HospitalUniversity of CambridgeUniversity of CambridgeUniversity of CambridgeUniversity of CambridgeThe relationship between alternans and arrhythmogenicity was studied in genetically modified murine hearts modeling catecholaminergic polymorphic ventricular tachycardia (CPVT) during Langendorff perfusion, before and after treatment with catecholamines and a β-adrenergic antagonist. Heterozygous (RyR2p/s) and homozygous (RyR2s/s) RyR2-P2328S hearts, and wild-type (WT) controls, were studied before and after treatment with epinephrine (100 nM and 1 µM) and propranolol (100 nM). Monophasic action potential recordings demonstrated significantly greater incidences of arrhythmia in RyR2s/p and RyR2s/s hearts as compared to WTs. Arrhythmogenicity in RyR2s/s hearts was associated with alternans, particularly at short baseline cycle lengths. Both phenomena were significantly accentuated by treatment with epinephrine and significantly diminished by treatment with propranolol, in full agreement with clinical expectations. These changes took place, however, despite an absence of changes in action potential durations, ventricular effective refractory periods or restitution curve characteristics. Furthermore pooled data from all hearts in which arrhythmia occurred demonstrated significantly greater alternans magnitudes, but similar restitution curve slopes, to hearts that did not demonstrate arrhythmia. These findings thus further validate the RyR2-P2328S murine heart as a model for human CPVT, confirming an alternans phenotype in common with murine genetic models of the Brugada syndrome and the congenital long-QT syndrome type 3. In contrast to these latter similarities, however, this report demonstrates the dissociation of alternans from changes in the properties of restitution curves for the first time in a murine model of a human arrhythmic syndrome.http://journal.frontiersin.org/Journal/10.3389/fphys.2010.00126/fullBrugada SyndromeCatecholaminergic polymorphic ventricular tachycardiaarrhythmiaSudden cardiac deathalternansryanodine Receptor
spellingShingle Ian N Sabir
Ian N Sabir
Nan Ma
Victoria Jones
Catharine A Goddard
Yanmin Zhang
Yanmin Zhang
Asli Kalin
Andrew Grace
Andrew Grace
Christopher Huang
Christopher Huang
Alternans in genetically modified Langendorff-perfused murine hearts modeling catecholaminergic polymorphic ventricular tachycardia
Frontiers in Physiology
Brugada Syndrome
Catecholaminergic polymorphic ventricular tachycardia
arrhythmia
Sudden cardiac death
alternans
ryanodine Receptor
title Alternans in genetically modified Langendorff-perfused murine hearts modeling catecholaminergic polymorphic ventricular tachycardia
title_full Alternans in genetically modified Langendorff-perfused murine hearts modeling catecholaminergic polymorphic ventricular tachycardia
title_fullStr Alternans in genetically modified Langendorff-perfused murine hearts modeling catecholaminergic polymorphic ventricular tachycardia
title_full_unstemmed Alternans in genetically modified Langendorff-perfused murine hearts modeling catecholaminergic polymorphic ventricular tachycardia
title_short Alternans in genetically modified Langendorff-perfused murine hearts modeling catecholaminergic polymorphic ventricular tachycardia
title_sort alternans in genetically modified langendorff perfused murine hearts modeling catecholaminergic polymorphic ventricular tachycardia
topic Brugada Syndrome
Catecholaminergic polymorphic ventricular tachycardia
arrhythmia
Sudden cardiac death
alternans
ryanodine Receptor
url http://journal.frontiersin.org/Journal/10.3389/fphys.2010.00126/full
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