OBJECTIVE
This study was conducted to determine the effects of carvedilol adjunct to standard treatment on left ventricular function (LVF), estimated as ejection fraction (EF) and fractional shortening (FS) on echocardiography, in children with idiopathic dilated cardiomyopathy (DCM). A secondary end point was to characterize the antioxidant potential of carvedilol.
METHODS
Hospitalized children aged RESULTS
Twenty-one children (12 boys, 9 girls; age range, 7 months to 16 years; 100% white) completed the study. Four patients discontinued carvedilol at the beginning of the study due to severe arrhythmia which required amiodarone therapy (2 patients), bradycardia and hypotension (1), and bronchospasm (1). Carvedilol (0.4 mg/kg/d in children 62.5 kg) was associated with significant decreases from baseline in systolic BP (130 [4] vs 123 [3] mm Hg; P<0.05), diastolic BP (85 [4] vs 77 [4] mm Hg; P<0.05), and HR (81 [4] vs 65 [4] bpm; P<0.001) after the first month of addition to standard therapy. At 6 months, there were significant improvements from baseline in EF (37.2% [2.4%] vs 50.2% [2.3%]; P<0.001) and FS (18.37% [2.00%] vs 23.58% [0.90%]; P<0.001). Modified NYHAC class was significantly improved in 80% of children (2.9 vs 2.3; P<0.001) at 12 months. The highest dose of carvedilol (0.8 mg/kg/d in children 62.5 kg) was well tolerated in all 21 children. No serious AEs that necessitated study drug discontinuation (tiredness, headache, vomiting) were observed. At baseline, mean (SE) erythrocyte SOD activity (2781 [116] vs 2406 [102] U/g Hb; P<0.05) and GR activity (5.3 [0.3] vs 3.0 [0.2] micromol nicotinamide adenine dinucleotide phosphate [NADPH]/min/g Hb; P<0.001) were significantly higher in children with DCM who received standard therapy compared with healthy controls.CAT activity (12.7[0.9] vs 18.5 [1.0]U/g Hb; P<0.001) was significantly lower, while GSH-Px was unchanged. At 6 and 12 months of therapy, carvedilol plus standard treatment was associated with significant decreases from baseline in SOD (2516 [126] and 2550 [118], respectively, vs 2781 [116] U/g Hb; both, P<0.001) and GR (4.7 [0.3] and 4.1 [0.2], respectively, vs 5.3 [0.2] micromol NADPH/min/g Hb; P<0.05 and P<0.001) and increased CAT (16.9 [1.0] and 16.4 [0.7], respectively, vs 12.7 [0.9] U/g Hb; both, P<0.001).
CONCLUSIONS
These pediatric patients with DCM treated for 12 months with carvedilol (up to 0.8 mg/kg/d in children 62.5 kg) were found to have significant improvements in LVF and symptoms of HF. Twelve months of carvedilol therapy was associated with antioxidant enzyme activities near those observed in healthy children.
