STATE-OF-THE-ART PAPER
Arrhythmia Predisposition
Between Rare Disease Paradigms and Common Ion Channel Gene Variants
Eric Schulze-Bahr, MD*,
,
,*
* Leibniz Institute for Arteriosclerosis Research (LIFA), Molecular Cardiology, University of Münster, Münster, Germany
Department of Cardiology and Angiology, University Hospital, University of Münster, Münster, Germany
Interdisciplinary Center for Clinical Research (IZKF), Münster, Germany
Manuscript received January 19, 2006;
revised manuscript received April 28, 2006,
accepted May 1, 2006.
* Reprint requests and correspondence: Dr. Eric Schulze-Bahr, Molekular-Kardiologie, Leibniz-Institut für Arterioskleroseforschung (LIFA) an der Westfälischen Wilhelms-Universität Münster, Domagkstr. 3, D-48149 Münster, Germany (Email: Eric.Schulze-Bahr{at}ukmuenster.de).
Cardiac side effects, such as QT prolongation or occurrence of Torsade de pointes (TdP), from widely used cardiac and non-cardiac drugs are still a major challenge for physicians. Recent advances in knowledge on the physiology of myocardial repolarization have made it clear that alterations of ion channel genes are associated with diverse in vitro effects that may tune normal repolarization to critical edges where ventricular arrhythmia occurs. The extent to which genetic factors (aside from "typical" ion channel gene mutations) are associated with susceptibility to TdP remains to be determined and is addressed in this review. Future research must: 1) identify all relevant genes for repolarization; 2) determine the extent to which the variability of the QT interval and of the response to action potential prolongation is genetically controlled; 3) investigate the role of functionally relevant single nucleotide polymorphisms/haplotype constellations to the contribution to repolarization; and 4) integrate identified genetic factors with other known factors for TdP risk, according to their relative importance, in a network algorithm for arrhythmogenesis. Gaining an understanding of the current genetic and genomic data of patients with drug-induced arrhythmia are the first steps to overcoming the hurdles associated with unexpected cardiac side effects of a variety of drugs.
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Abbreviations and Acronyms
| | BrS = Brugada syndrome | | CPVT = catecholaminergic polymorphic ventricular tachycardia | | HERG = human ether-a-go-go gene | | I = ionic current | | LQTS = long-QT syndrome | | SCD = sudden cardiac death | | SNP = single nucleotide polymorphism | | SQTS = short-QT syndrome | | TdP = Torsade de pointes | | VT = ventricular tachycardia |
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Copyright © 2006 by the American College of Cardiology Foundation.