QTc and QRS Abnormalities are Associated with Outcome in Pediatric Heart Failure.

Adult studies have shown that depolarization and repolarization abnormalities are associated with worsening heart failure; however, this relationship is not well understood in pediatric congenital heart disease. We evaluated the association between QTc and QRS duration to systolic function and outcome in children with heart failure and reduced ejection fraction (HFrEF). We performed a retrospective, single-center, 14-year cohort study of HFrEF children. Clinical records, echocardiograms, and electrocardiograms were reviewed for every clinical encounter. Diagnosis, interventions, outcomes, QRS and QTc duration, and systolic function were collected. Repeated-measure ANOVA evaluated the association between depolarization and repolarization to cardiac function. Cox regression analysis examined the effects of age, time since diagnosis, and measured and change in QTc and QRS duration on time to transplant/death. We enrolled 136 cardiomyopathy (CM) and 47 structural heart disease (SHD) patients. Prolonged QRS (p = 0.0001) and QTc (p = 0.02) were associated with systolic dysfunction. This association was significant in SHD group (QRS p < 0.0001, QTc p = 0.048), but not CM group (QRS p = 0.5, QTc p = 0.3). Progressive lengthening of QTc was significantly associated with transplant or death in the overall cohort (HR 1.02, CI 1.011-1.028), SHD, (HR 1.020, CI 1.001-1.039), and CM (HR 1.017, CI 1.007-1.027). QTc and QRS prolongation are each associated with ventricular dysfunction in pediatric SHD with heart failure. QTc prolongation is an indication for poor outcomes in SHD and CM groups, leading to a higher risk of death or transplantation. Progressive lengthening of QTc over time in children with HFrEF may indicate increased risk in this population.