[Dilated cardiomyopathy and growth hormone]

The data from animal and human in vivo studies suggest that cardiac function is dependent in part on the normal function of the GH/IGF-1 axis (growth hormone/insulin-like growth factor-1). So far encouraging results from phase II and III clinical trials evaluating the effects of intermittent GH treatment in patients with chronic congestive heart failure (CHF) due to dilated cardiomyopathy (DCM) have been published. In these studies, growth hormone (i.e., DNA-derived recombinant human growth hormone) was not used alone but in addition to standard optimal therapy for CHF. The following rationale is the basis of this new approach for the treatment of CHF due to DCM: According to Laplace's Law cardiac wall stress (i.e., the force acting per unit of cross-sectional area of the ventricular wall) is directly related to intraventricular pressure and ventricular radius and inversely related to ventricular wall thickness. Cardiac (ventricular) wall stress is increased in DCM (mainly because of the dilatation of the ventricles and to a minor extent because of the relative reduction in ventricular thickness). GH is capable of increasing ventricular wall thickness in DCM thus reducing cardiac wall stress which in turn leads to an improvement in systolic cardiac performance.