[Therapy of dilated cardiomyopathy with recombinant human growth hormone]

Dilated cardiomyopathy is a disease of the myocardium which is characterized by predominant enlargement of the left ventricle, decreased systolic function, and reduced myocardial wall thickness. The reduction in the number and function of myocardial fibers induces hypertrophy and leads to interstitial fibrosis. Ventricular dilatation and reduced wall thickness contributes to a further increase of the already elevated myocardial wall stress and triggers the continuous decrease of myocardial function. The initial myocyte injury by different and mostly unknown causes leads to progressive myocyte damage resulting in a similar uniform clinical picture independent from the initial myocellular derangement. One of the common pathways may be an inadequate response of the heart to human growth hormone (GH). Several studies support this hypothesis: GH deficiency results in a significant reduction of ventricular wall thickness and myocardial function, and GH-substitution is able to normalize the depressed left ventricular function. In addition, Sacca et al. reported in an uncontrolled study that GH-therapy reduced left ventricular wall stress by 40% in 7 patients with dilated cardiomyopathy. There was a parallel increase of the ejection fraction from 34% to 47%. This improvement was accompanied by a decrease of the functional classification of heart failure from NYHA 2.7 to 1.6. This therapeutic approach to alter the myocyte function directly by growth factors may open a new therapeutic concept in dilated cardiomyopathy. If double blind, randomized studies confirm the results of Sacca's study, a new era of therapeutic options may be available for the treatment of dilated cardiomyopathy.