Repolarization abnormalities and their arrhythmogenic consequences in porcine tachycardia-induced cardiomyopathy.

Objectives: Action potential prolongation related to the alteration of several membrane currents is constantly reported in heart failure (HF) but reports about its role in arrhythmogenesis are sparse. Our aim was to determine, by analogy with long QT syndromes, whether prolonged repolarization is associated with increased dispersion or linked to bradycardia-dependent ventricular arrhythmias in pacing-induced cardiomyopathy.

Methods: QT intervals, action potentials and transmural activation-to-recovery intervals (ARIs) along with whole-cell delayed rectifier (I(K)) and transient outward (I(to1)) K+ currents were recorded in left ventricle from pigs with HF and controls.