Biventricular pacing and heterogeneity of ventricular repolarization in heart failure patients
Abstract:
Overview
Objective. The aim of our study was to evaluate the effect of cardiac resyncronization
therapy (CRT) on QT dispersion (QTd), JT dispersion (JTd) and transmural dispersion of repolarization
(TDR), markers of heterogeneity of ventricular repolarization in a study population
with severe heart failure.
Methods and Results. Fifty patients (43 male, 7 female, aged 60.2 ± 3.1 years) suffering from
congestive heart failure (N = 39 NYHA class III; N = 11 NYHA class IV) as a result of coronary
artery disease (N = 19) or of dilated cardiomyopathy (N = 31), sinus rhythm, QRS duration >130
ms (mean QRS duration >156 ± 21 ms), an ejection fraction < 35%, left ventricular end-diastolic
diameter >55 mm, underwent permanent biventricular DDDR pacemaker implantation. A 12-lead
standard electrocardiogram was performed at baseline, during right-, left-, and biventricular
pacing and QTd, JTd and TDR were assessed. Biventricular pacing significantly reduced QTd
(73.93 ± 19.4 ms during BiVP vs 91 ± 6.7 ms at sinus rhythm, p = 0.004), JTd (73.18 ± 17.16 ms
during BiVP vs 100.72 ± 39.04 at baseline p = 0.003), TDR (93.16 ± 15.60 vs 101.55 ± 19.08 at
baseline; p<0.004), as compared to sinus rhythm. Right ventricular endocardial pacing and left
ventricular epicardial pacing both enhanced QTd (RVendoP 94 ± 51 ms, p<0.03; LVepiP 116 ±
71 ms, p<0.02) and TDR (RVendoP 108.13 ± 19.94 ms; p<0.002; LVepiP 114.71 ± 26.1;
p<0.05).There was no effect on JTd during right and left ventricular stimulation.
Conclusions. Biventricular pacing causes a statistically significant reduction of ventricular heterogeneity
of ripolarization and has an electrophysiological antiarrhythmic influence on arrhythmogenic
substrate of dilatative cardiomiopathy. (Heart International 2006; 2: 27-32)
Keywords
Biventricular pacing, QT dispersion, JT dispersion, TDR, Heart failure
Article:
Article Information:
Correspondence
Vincenzo Russo, MD, Via della Resistenza, 48, 80021 Afragola (NA) – Italy, v.p.russo@libero.it
