Bundle Branch Area Pacing in Patients With Moderate to Complex Biventricular Congenital Heart Disease

INTRODUCTION: Pacing-induced cardiomyopathy in patients with congenital heart disease (CHD) is a cause of significant morbidity. Reports of bundle branch area pacing (BBAP) in this population remain limited. METHODS AND RESULTS: Eighteen patients with moderate to complex biventricular CHD, as defined by the Bethesda criteria, underwent BBAP attempt with success in 15 (83%). The median age at implant was 17 years (IQR 13, 40). Among the patients with successful BBAP, the median QRSd was 128 ms (IQR 120, 132), and the median V6-RWPT was 72 ms (IQR 58, 80). In the subgroup of patients who underwent successful BBAP for improved synchrony, there was a significant reduction in the QRSd (167 ms [IQR 147 186] vs. 132 ms [IQR 127 135]; p = 0.01). Electrical parameters remained stable over 4-6 months of follow-up apart from threshold, which had a statistically significant but clinically irrelevant rise; this was followed by stabilization (threshold at last follow-up was 0.75 V at 0.4 ms [IQR 0.7 V, 1 V]). Before- and after-pacing ejection fraction (EF) was unchanged in systemic left ventricle (LV) group (LVEF 58% [IQR 48%, 62%] vs. 60% [IQR 54%, 64%]; p = 0.44). There was a non-statistically significant trend towards improvement in the systemic right ventricle (RV) group (RV fractional area change 26.1% [IQR 20.9%, 28.5%] vs. 30.2% [IQR 24.6%, 32.8%]; p = 0.07). CONCLUSIONS: The use of BBAP in patients with moderate to complex biventricular CHD appears to be safe and feasible. The modality delivers good electrical synchrony with lead parameters remaining within normal limits.