Predictors of an adverse clinical outcome in patients with long-term right ventricular apical pacing

Right ventricular (RV) apical pacing can result in progressive left ventricular (LV) dysfunction and contribute to the development of heart failure (HF). This study aimed to predict the outcome after long-term RV apical pacing in patients with acquired atrioventricular (AV) block who required permanent pacing.

We included 247 patients who underwent long-term (>90% ventricular pacing with atrioventricular synchrony for more than 1 year) RV apical pacing for acquired AV block. We excluded patients with a reduced LV systolic function [ejection fraction (EF) <50%]. The paced QRS duration, degree of the axis, clinical characteristics, laboratory findings, and echocardiographic parameters were recorded. We evaluated the mortality and hospitalization due to HF.

The mean follow-up duration was 6.9 years. Mortality and hospitalization due to HF occurred in 8.1% and 17%, respectively. In a multivariate analysis, a wider paced QRS duration and less superior paced QRS axis at the time of the implantation were independent risk factors for adverse events. The patients with a paced QRS duration of ≥163ms and axis of ≥-65° had a 5.8 times higher risk for adverse events compared to those with a paced QRS duration of <163ms and axis of <-65°.

The paced QRS duration and axis could help us predict adverse clinical outcomes after permanent RV apical pacing in patients with high-degree AV block.