Nonalternans repolarization variability and arrhythmia – the calcium connection

Abstract Repolarization alternans precedes certain types of ventricular arrhythmias and its presence may be prognostically useful, but some ventricular arrhythmias are not preceded by repolarization alternans. Nonalternans changes of ventricular repolarization occur in patients with coronary artery...

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Bibliographic Details
Published in:Journal of electrocardiology 2016-11, Vol.49 (6), p.877-882
Main Author: Nemec, Jan
Format: Article
Language:English
Subjects:
Action Potentials
Animal research
Animals
Calcium
Calcium - metabolism
Calcium Signaling
Cardiac arrhythmia
Cardiovascular
Electrocardiography
Evidence-Based Medicine
Heart Conduction System - physiopathology
Heart Rate
Humans
Long QT syndrome
Long QT Syndrome - complications
Long QT Syndrome - physiopathology
Models, Cardiovascular
Nonalternans repolarization variability
Risk factors
Tachycardia, Ventricular - complications
Tachycardia, Ventricular - physiopathology
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Summary:Abstract Repolarization alternans precedes certain types of ventricular arrhythmias and its presence may be prognostically useful, but some ventricular arrhythmias are not preceded by repolarization alternans. Nonalternans changes of ventricular repolarization occur in patients with coronary artery disease and in subjects with congenital long QT syndrome. In animal experiments, nonalternans repolarization lability occurs in a canine model of chronic AV block with propensity to polymorphic ventricular tachycardia, in the perfused rabbit heart exposed to IKr block, and in a murine model of catecholaminergic polymorphic ventricular tachycardia. Optical mapping experiments indicate that heterogeneity of intracellular calcium handling underlies nonalternans repolarization variability. Detection of nonalternans repolarization lability poses specific challenges, since signal averaging does not increase the signal to noise ratio. Nonalternans repolarization lability may be erroneously reported as repolarization alternans by non-spectral methods applied to short data segments. Additional research will be needed to determine the role of nonalternans repolarization variability in mechanism of ventricular arrhythmias.
ISSN:0022-0736
1532-8430
DOI:10.1016/j.jelectrocard.2016.08.003