Impact and Modifiers of Ventricular Pacing in Patients With Single Ventricle Circulation.

BACKGROUND

Palliation of the single ventricle (SV) circulation is associated with a burden of lifelong complications. Previous studies have identified that the need for a permanent ventricular pacing system (PPM) may be associated with additional adverse long-term outcomes.

OBJECTIVES

The goal of this study was to quantify the attributable risk of PPM in patients with SV, and to identify modifiable risk factors.

METHODS

This international study was sponsored by the Pediatric and Congenital Electrophysiology Society. Centers contributed baseline and longitudinal data for functionally SV patients with PPM. Enrollment was at implantation. Controls were matched 1:1 to PPM subjects by ventricular morphology and sex, identified within center, and enrolled at matched age. Primary outcome was transplantation or death.

RESULTS

In total, 236 PPM subjects and 213 matched controls were identified (22 centers, 9 countries). Median age at enrollment was 5.3 years (quartiles: 1.5-13.2 years), follow-up 6.9 years (3.4-11.6 years). Median percent ventricular pacing (Vp) was 90.8% (25th-75th percentile: 4.3%-100%) in the PPM cohort. Across 213 matched pairs, multivariable HR for death/transplant associated with PPM was 3.8 (95% CI 1.9-7.6; P < 0.001). Within the PPM population, higher Vp (HR: 1.009 per %; P = 0.009), higher QRS z-score (HR: 1.19; P = 0.009) and nonapical lead position (HR: 2.17; P = 0.042) were all associated with death/transplantation.

CONCLUSIONS

PPM in patients with SV is associated with increased risk of heart transplantation and death, despite controlling for increased associated morbidity of the PPM cohort. Increased Vp, higher QRS z-score, and nonapical ventricular lead position are all associated with higher risk of adverse outcome and may be modifiable risk factors.