Safety and Tolerability of Chronic Carvedilol in Pediatric Dilated Cardiomyopathy: A Report from the Pediatric Cardiomyopathy Registry

Long-term studies on safety of beta-blockers in pediatric heart failure (HF) are scant. We describe the safety profile, dose ranges, and tolerability of carvedilol in pediatric dilated cardiomyopathy (DCM). The Pediatric Cardiomyopathy Registry (PCMR) was used to identify patients with DCM, treated with carvedilol from 1997 to 2005. Descriptive statistics were analyzed and echocardiographic parameters were compared longitudinally using ANOVA. Total 118 patients were included with median age 4.4 years (interquartile range (IQR) 1.0-13.3). The etiology of DCM was idiopathic (66%), myocarditis (14%), familial DCM (21%). Majority (63%) had symptoms of HF at diagnosis and were on an angiotensin-converting enzyme inhibitor (ACEi) (95%) at carvedilol initiation. The mean ± standard deviation (SD) carvedilol dose at 1 year was 0.38 ± 0.44 mg/kg/dose. The median duration of carvedilol therapy studied was 361 days (IQR 101-958) with 18% of the patients treated for > 3 years. Few patients (< 10%) had blood pressure or heart rate below safety thresholds with no admission for hypotension or bradycardia. Only 4 patients discontinued carvedilol for bradycardia (n = 1), fatigue (n = 1), poor LV function (n = 1) and worsening renal function (n = 1). Mean left ventricular shortening fraction (LVFS) was 16% ± 8 at carvedilol initiation (n = 98), 21% ± 9 at 1 year (n = 49) and 23% ± 9 at 2 years (n = 20) post-carvedilol initiation, suggesting a possible clinical benefit (p < 0.01). These results provide safety data for chronic carvedilol use in children and show a low prevalence of discontinuation for adverse events. Further study of the long-term remodeling effects of chronic beta-blocker use in pediatric HF is required.