Should β-blockers be used for the treatment of pediatric patients with chronic heart failure?

In multiple clinical trials, β-blockers have been shown to significantly improve morbidity and mortality in adults with chronic congestive heart failure, but there is little reported experience with their use in children. Heart failure involves activation of the adrenergic nervous system and other neurohumoral systems in order to maintain cardiovascular homeostasis. These compensatory mechanisms have been shown to cause myocardial damage with chronic activation, which has been hypothesized to be a major contributing factor to the clinical deterioration of adults with heart failure. Studies have demonstrated inhibition of this neurohumoral response and concomitant clinical benefits with β-blockers. Consequently, β-blockers have evolved to become an important part of comprehensive medical therapy for congestive heart failure in adults. Pediatric heart failure represents an entirely different spectrum of disease, caused more commonly by congenital heart disease than cardiomyopathy. Surgical palliation and correction are important components of pediatric heart failure therapy, and residual, postsurgical cardiac lesions can lead to chronic heart failure. Although neurohumoral activation in children is similar to that in adults with heart failure, there are important differences from adults in physiology and developmental changes that are especially observed in infants. Current published clinical experience with β-blocker use in children with heart failure is limited to case series with relatively small numbers of patients. Nevertheless, these series show consistent symptomatic improvement, and improvement in ventricular systolic function in patients with cardiomyopathies and congenital heart disease, similar to findings in adults. Adverse effects were common and many patients in these studies had adverse outcomes (death and/or need for transplantation). One study has noted differences in pharmacokinetics in children compared with adults. However, a multicenter, randomized controlled trial to evaluate carvedilol in pediatric heart failure from systolic ventricular dysfunction is currently ongoing and should help to clarify the efficacy and tolerability of carvedilol in children.