PEDIATRIC CARDIOLOGY FELLOW University of Toronto Toronto, Ontario, Canada
Background: The prevalence of pacemaker-induced cardiomyopathy (PICM) appears to have decreased due to the shift from apical to septal transvenous ventricular lead placement. However, data on the prevalence of pediatric PICM in a contemporary cohort is limited, which is especially important in an era where conduction system pacing has emerged as a preferred strategy.
METHODS AND RESULTS:
Methods: A retrospective single-centre cohort study including patients < 18 years with and without congenital heart disease and AV block who underwent transvenous pacing between 2010 and 2020 was performed. Patients were ≥20% ventricular paced with at least 2 years of follow-up. The primary outcome was the prevalence of PICM, defined as a decrease in left-ventricular ejection fraction (LVEF) by ≥10% from baseline and LVEF of < 50% at last follow-up.
Results: Forty-four children (61.4% female, mean age 10 ± 3.4 yrs) received transvenous single or dual chamber pacemakers. Eleven patients (25%) had congenital heart disease, nine of whom had undergone cardiac surgery (20.5%). Despite the intention of septal lead position, only 19 (43.2%) were located septal, whereas 10 (22.7%) were right-ventricular (RV) free wall and 15 (34.1%) were apical. The LVEF at the last follow-up compared to baseline was lower in apical pacing (68.5 vs. 62.3%, P=0.01) but unchanged in the other two pacing locations (RV free wall: 65.8 vs. 65.1%, P=0.76; septal: 66.3 vs. 63.8%, P=0.06). PICM occurred in two of our study patients thus far over a median follow-up of 5.4 yrs [IQR 3.2-9.0 yrs]. Both patients had significant conotruncal cardiac lesions requiring surgical repair followed by pacemaker implantation, one with a transvenous apical lead and the other with a septal lead position.
Conclusion: The PICM prevalence in our pediatric cohort was 4.5%. LV systolic function decreased in apical pacing but remained unchanged in the other two pacing locations. Non-apical transvenous pacing may be associated with preserved LVEF. Importantly, congenital heart disease was a stronger correlate to PICM than lead position and may be considered a risk factor when selecting pacing systems for these patients.
