June 22, 2007Open Access
Role of spatial dispersion of repolarization in inherited and acquired sudden cardiac death syndromes
Key Result
Amplification of transmural dispersion of repolarization serves as a common final pathway causing sudden cardiac death in long QT, short QT, Brugada, and catecholaminergic polymorphic VT syndromes.
Structured PICO
P
Population
Patients with inherited and acquired sudden cardiac death syndromes, including long QT, short QT, Brugada syndromes, and catecholaminergic polymorphic ventricular tachycardia
Amplification of spatial dispersion of repolarization serves as a common final pathway for sudden cardiac death across various inherited ion channelopathies despite their different phenotypes and etiologies.
Abstract
This review examines the role of spatial electrical heterogeneity within the ventricular myocardium on the function of the heart in health and disease. The cellular basis for transmural dispersion of repolarization (TDR) is reviewed, and the hypothesis that amplification of spatial dispersion of repolarization underlies the development of life-threatening ventricular arrhythmias associated with inherited ion channelopathies is evaluated. The role of TDR in long QT, short QT, and Brugada syndromes, as well as catecholaminergic polymorphic ventricular tachycardia (VT), is critically examined. In long QT syndrome, amplification of TDR is often secondary to preferential prolongation of the action potential duration (APD) of M cells; in Brugada syndrome, however, it is thought to be due to selective abbreviation of the APD of the right ventricular epicardium. Preferential abbreviation of APD of the endocardium or epicardium appears to be responsible for the amplification of TDR in short QT syndrome. In catecholaminergic polymorphic VT, reversal of the direction of activation of the ventricular wall is responsible for the increase in TDR. In conclusion, long QT, short QT, Brugada, and catecholaminergic polymorphic VT syndromes are pathologies with very different phenotypes and etiologies, but they share a common final pathway in causing sudden cardiac death.