Pacing-induced cardiomyopathy in children

Pacemaker therapy is a lifesaving treatment in children with advanced atrioventricular blocks. However, there is a concern regarding pacemaker-induced cardiomyopathy (PICM). Currently, there is a lack of data comparing the incidence of PICM in children with congenital complete atrioventricular block (cc-AVB) to postoperative atrioventricular block (po-AVB). We aimed to delineate the incidence of PICM in children in these groups.

This retrospective study included all children ≤15 years who received pacemakers for either cc-AVB or po-AVB between 1982 and 2021 in Denmark. Patients were identified from the Danish Pacemaker Registry. Demographics, device characteristics, and endpoints were validated from medical charts. PICM was defined as heart failure (HF) hospitalization, initiation of HF medication, deterioration of ejection fraction, heart transplantation, upgrade to cardiac resynchronization therapy, or HF-related mortality.

In total, 236 children were included. Median follow-up was 17.6 years, while the median age was 4.3 (IQR 0.5-9.94) and 2.2 (IQR 0.6-5.8) years for cc-AVB and po-AVB, respectively. The absolute risk of PICM after 30 years was 30% for the entire cohort. Po-AVB and age above median age were associated with an increased risk of PICM compared to cc-AVB (HR 2.98, 95% CI 1.64-5.42, p < 0.001, and HR 0.51, 95 % CI 0.28-0.92, p < 0.001), respectively. Age and indication demonstrated a significant interacting effect on PICM (pinteraction=0.03).

The incidence of PICM in children implanted with pacemakers is high – 30% after 30 years. Age and indication are both influencing factors for the development of PICM.