Safety and Efficacy Study of Carvedilol to Treat Children With Congestive Heart Failure

Overactivity of the sympathetic nervous system is thought to contribute to the pathophysiology of congestive heart failure (CHF). Blockade of the sympathetic nervous system with β-adrenergic inhibitors could be expected to ameliorate these detrimental effects in a manner analogous to the effects of the angiotensin converting enzyme inhibitors on the overactive renin-angiotensin system. Carvedilol may be superior to pure beta-blockers in the treatment of CHF through its mechanism of action of blocking not only β-receptors but also α-receptors, which would allow vasodilation to reduce the afterload on the failing heart. Since beta-blockers may initially produce a negative inotropic effect on the heart, long term treatment has been needed to show benefits of removal of the adrenergic stimulation. The investigators will monitor the safety and efficacy of carvedilol administration in children with chronic CHF due to systemic ventricular dysfunction.