Abstract 2135: Decreased Functional Status and Ventricular Function in Fontan Patients With Pacemakers
Background: Many Fontan patients (pts) require a pacemaker. Few studies have characterized paced Fontan pts.
Purpose: To compare clinical characteristics, functional status and ventricular performance in paced Fontan pts to non-paced pts.
Methods: The NHLBI-funded Pediatric Heart Network Fontan Cross-sectional Study characterized 546 Fontan survivors. Pts with pacemakers were identified. Cardiac rhythm was determined using ECGs at the time of study. Clinical characteristics and study outcomes (Child Health Questionnaire (CHQ), echo ventricular ejection fraction (EF), exercise testing) were obtained. There were 72 pts (13%) with a pacemaker, but only 43/72 (60%) were paced at the time of study ECG (paced pts). Paced pts were compared to the 474 without pacemakers (no pacemaker) and to the 29 pacemaker pts in a non-paced rhythm (non-paced).
Results: There were no differences in age at enrollment (12.5±3.7 vs 11.7±3.3 years, p = 0.2), age at Fontan (3.8±2.9 vs 3.4±2.0 years, p = 0.4), years since Fontan (8.8±3.8 vs 8.5±3.4 years, p = 0.5), anatomic diagnosis (p = 0.6), and Fontan type (p = 0.4) between paced pts and the no pacemaker group. Compared to no pacemaker pts, paced pts had undergone more surgical procedures since Fontan (0.9±1.7 vs 0.2±0.7, p = 0.007, excluding pacemaker placement), were more likely to have a history of thrombosis (19% vs 6%, p = 0.004), arrhythmia (72% vs 13%, p < 0.001) and ventricular failure (21% vs 10%, p = 0.04), and were taking a greater number of medications (3.6±2.2 vs 2.2±1.7, p < 0.001). CHQ physical summary scores were lower in paced pts (38.6±15.5 vs 46.1±11.2, p = 0.005), but exercise performance was similar between groups. EF Z score was lower (−1.9±2.1 vs −0.8±2.0, p = 0.007) in paced pts compared to no pacemaker. EF Z score was also lower in paced pts compared to non-paced pacemaker pts (−1.9±2.1 vs −0.8±1.6, p = 0.049), but no other differences were present between these two groups.
Conclusions: Paced Fontan pts have increased medical morbidity, poorer functional status, and echo evidence of worse ventricular systolic function compared to Fontan pts without a pacemaker. Understanding mechanisms by which pacing is associated with worse outcome in Fontan pts may have implications for future, alternative pacing strategies.