Prevalence and clinical predictors for new-onset heart failure after permanent Right Ventricular Apical pacing in patients with acquired high-grade atrioventricular block

Abstract

Background: Previous studies have demonstrated that long-term right ventricularapical pacing (RVA) lead to left ventricular (LV) dyssynchrony, worsening of LV function, and development of heart failure (HF). However, permanent RVA pacing is required in patients (pts) with high-degree atrioventricular (AVB). There is limited data on the prevalence and clinical predictors for the development of HF after RVA pacing in pts with acquired AVB. Methods and Results: We studied the clinical outcomes after long-term RVA pacing in 304 pts suffered from acquired high-grade AVB without prior history of HF. All pts had >90% RVA pacing as determined by device diagnostic data. At a mean of 99 mths, 77 pts (25%) developed HF after a mean of 77 mths of (2-332 mths) RVA pacing. As compared to pts without HF, pts developed HF were older at the time of implant (72±11 vs. 67±15 yrs, p<0.01), had a higher incidence of diabetes (38 vs. 23%, p<0.01), new onset of myocardial infarction (MI, 16 vs. 3%, p=0.014) and atrial fibrillation (19 vs. 7%, p<0.01), wider pacing QRS duration (170±18 vs. 159±16ms, p<0.01), and more likely to receive VVI pacemaker (34 vs. 14%, p<0.01). However, there were no significance in male gender (47 vs. 44%), duration of pacing (72±11 vs. 67±15 mths) and baseline LV ejection fraction (62±9 vs. 66±12%) between pts with or without HF (p<0.05). Furthermore, pts with HF had significantly higher mortality than pts without HF (62 vs. 23%, p<0.01). Cox-regression analysis demonstrated that elderly age at implant (Odd ratio [OR] 1.07, p<0.01), wider pacing QRS duration (OR 1.03, p<0.01), new onset of MI (OR 3.06, p=0.01) and VVI pacemaker (OR 1.99, p=0.027) predict the development of new-onset HF. Conclusions: A significant proportion (1/4) of pts with AVB developed new-onset HF after RVA pacing. The age at the time of implant, wider pacing QRS duration, the onset of MI and VVI pacing, but not the duration of pacing and their coexsiting condition, predict the development of HF after RVA pacing. More importantly, the development of HF after RVA pacing is associated with a high mortality on long-term follow-up. Whether alternative ventricukar site or biventricular pacing can prevent new-onset of HF in pts with AVB requiring long-term pacing remain unclear.