Anodal stimulation in pediatric patients with permanent epicardial ventricular pacemakers

Objectives We aimed to measure the frequency and factors associated with anodal stimulation in a pediatric population with epicardial pacing leads. Background In bipolar pacemakers, capture of the myocardium typically occurs at the cathode. However, AS with capture at the anode has been described. This has not been described in epicardial pacemakers. Methods Retrospective data were collected from patients ≤ 21 years of age with permanent bipolar epicardial ventricular pacemakers from 1/2017 to 1/2018. AS was defined as a clear change on surface ECG in at least one of the 12 leads assessed by two blinded pediatric electrophysiologists. Results Twenty‐four bipolar leads in 23 patients were included in the study. One patient had both biventricular leads tested. Median age was 7.1 years (IQR 5.0–10.9), weight was 20.9 kg (IQR 16.5–33.5), and 65% were male. Testing was performed at a median of 2.8 years (IQR 1.6–6.1) after implant. Congenital heart disease was present in 57%. Complete heart block was the pacemaker indication in 78%. AS was identified in 16/24 (67%) of leads tested. Identification of AS was associated with presence of congenital heart disease (p = 0.004) and 3DD between electrodes (p = 0.04). Conclusions AS is common in pediatric patients and was associated with a history of congenital heart disease and greater estimated 3DD between electrodes. The prevalent nature of AS may allow clinicians to utilize existing pacemakers as multisite pacing systems.