Post-pacemaker implant QRS duration and heart failure admission in patients with sick sinus syndrome and complete atrioventricular block.

ABSTRACT

AIMS: High demand right ventricular pacing may elicit left ventricular systolic dysfunction known as pacing-induced cardiomyopathy, increasing the risks of heart failure (HF) hospitalization. Percentage of demand ventricular pacing is different between patients with sick sinus syndrome (SSS) and those with complete atrioventricular block (CAVB). This study aims to compare the incidence of HF admission and pacing-induced cardiomyopathy between patients with SSS and CAVB. METHODS AND RESULTS: A total of 824 patients who received single ventricular or dual-chamber pacemaker implantation at our hospital between January 2003 and December 2012 were recruited for the study. Patients with HF, those without complete cardiac echocardiography, and those with significant coronary artery disease were excluded. Finally, 315 patients with SSS and 289 patients with CAVB were enrolled in this study. The CAVB group had a higher pacing percentage (39.37 ± 9.17% vs. 83.82 ± 33.06%; P < 0.001), longer pacing QRS duration (142.56 ± 33.02 ms vs. 156.63 ± 25.18 ms; P < 0.001), and higher prevalence of follow-up left ventricular ejection fraction ≤40% (1.3% vs. 4.2%; P = 0.040). However, the incidence of HF admission was similar between the two groups (log-rank P = 0.647). Age [hazard ratio (HR), 95% confidence interval (CI) 1.121, 1.054-1.193], diabetes mellitus (HR, 95% CI 2.667, 1.159-6.136), pacing QRS duration ≥163 ms (HR, 95% CI 3.506, 1.491-8.247), and left atrial size (HR, 95% CI 1.070, 1.012-1.131) were independent predictors of HF admission. The Kaplan-Meier curve showed a significant difference in HF admission over a 3.5 year follow-up period (3.5 years P value = 0.004; 5 years P value = 0.002) between patients with pacing QRS duration ≥163 and <163 ms. CONCLUSIONS: There was no difference in HF admission between patients with SSS and CAVB, although the CAVB group had a higher pacing percentage. Post-pacemaker implant pacing QRS duration ≥163 ms was the most important predictor of HF admission.