Address for correspondence : Bibhuti B Das, MD, Division of Pediatric Cardiology, Suite # 334, University of Louisville, Louisville, KY 40202, USA. E-mail: bdas99@hotmail.com

Abstract:

The pace at which the base of knowledge has expanded, and the number of new studies published, there is a need to rethink future management of heart failure in children and young adults. The clinical evidences from adults suggest that the neurohormonal explanation of progression of heart failure is not complete and ventricular remodeling is an important pathophysiologic mechanism for initiation and progression of heart failure. Therefore, treatment of heart failure should be aimed both at neurohormonal modulation and at reversing the ventricular remodeling process. In this review we have discussed not only conventional remedies, but also newer drugs and therapies that are on the horizon, including angiotensin-converting enzyme inhibitors, beta-blockers, exogenous brain natriuretic peptide (nesiritide), blockers of angiotensin-receptors, calcium sensitizing agents, modulation of the cytokine response, endothelin receptor antagonists, vasopressin antagonists, chronic resynchronization therapy and/or implantable defibrillator, and implantable circulatory assist device support for heart failure in children and young adults. The need to care effectively for the increasing population of children and young adults with heart failure urges more prospective controlled studies in children to improve prognosis of heart failure.

Keywords : pediatric heart failure, left ventricular remodeling, carvedilol, nesiritide, levosimendan, cardiac resynchronization therapy, ventricular assist device, pediatric heart transplantation

Introduction:

As per the American College of Cardiology/American Heart Association task force on practice guidelines published in 2005 the term "heart failure" is preferred over the older term "congestive heart failure". (1) Even after two decades of success with neurohormonal inhibition, heart failure still remains the number one killer in adults and many patients still experience progression of their disease. (2) In children, the scope of the problem is less well defined. Data from the Pediatric Cardiomyopathy Registry published in 2004 indicated an annual incidence of 1.13 cases of cardiomyopathy per 100,000 children. (3) While some of this represent asymptomatic disease, nonetheless, the burden of disease overall is quite high. In the Pediatric Cardiomyopathy Registry, the majority of children with cardiomyopathy also had heart failure , with mortality rate of 13.6% at 2 years in dilated forms of cardiomyopathy. (3) It has been estimated that the annual incidence of heart failure from structural defects is 0.1-0.2% of live births.(4)

The American College of Cardiology/American Heart Association - 2005 guidelines excluded heart failure in children for two reasons: (1) because the underlying causes of heart failure in children differ from those in adults and (2) because none of the controlled trials of treatments for heart failure have included children. (1) Although the etiology of heart failure in adults is different from children, hemodynamic consequences and neurohormonal activation are remarkably similar. (5-8) In 2004, the practice guidelines for management of heart failure in children was published and followed the format of adults heart failure guidelines. (9) This review discusses what is known and not known about the relative efficacy and safety of available treatment choices for our growing populations of children and young adults with heart failure.

Etiology :

Despite advancement in surgical management, chronic heart failure in children is frequently associated with congenital heart disease. Chronic heart failure occurs most commonly in these patients as a result of excessive ventricular volume overload, pressure overload, post-operative cardiac sequelae with residual lesions or myocardial damage, pulmonary vascular disease, or consequence of chronic hypoxia. Other causes of chronic heart failure in children are cardiomyopathy (hypertrophic, dilated, restrictive, or non-compaction), congenital or acquired coronary artery abnormalities, endocarditis, Eisenmenger syndrome, primary pulmonary hypertension, cor pulmonale, incessant tachyarrhythmias, chronic anemias, and rheumatic heart diseases. Among the cardiomyopathy, dilated cardiomyopathy accounts for most cases of chronic heart failure in children. The underlying cause of dilated cardiomyopathy includes a wide variety of etiologies: idiopathic, inherited, infective, infiltrative, nutritional, iatrogenic or toxic, and cardiomyopathy associated with generalized muscle disease or mitochondrial disorders. Generally 30% of cases of myocarditis result in chronic heart failure . (10) Mason et al found evidence of myocarditis in 10% of adults with new-onset heart failure who did not have coronary heart disease. It is likely that this figure is much higher in children without structural heart disease. (11)