Effect of growth hormone on cardiac function.

At present, there is a growing body of evidence implicating growth hormone (GH) and/or insulin-like growth factor-I (IGF-I) in the intricate cascade of events connected with the regulation of heart development and hypertrophy. In addition, advanced clinical manifestations of abnormal GH levels almost always include impaired cardiac function, which may reduce life expectancy. This finding is related both to a primary impairment of heart structure and function and to metabolic changes such as hyperlipidaemia, increased body fat and premature atherosclerosis. Acromegalic cardiomyopathy is better correlated with disease duration than with GH or IGF-I levels. Myocardial hypertrophy with interstitial fibrosis, lymphomononuclear infiltration and areas of monocyte necrosis often result in increased right and left ventricular mass concentric hypertrophy. Conversely, patients with childhood or adult-onset GH deficiency (GHD) have a reduced left ventricular mass (LVM) and ejection fraction (EF) and the indices of left ventricular systolic function remained markedly depressed during exercise. Cardiac function is reported to improve during octreotide and GH replacement treatment in acromegaly and GHD, respectively. The evidence that GH can increase cardiac mass suggests its use in the treatment of idiopathic dilated cardiomyopathy. In a recent study on such patients, the administration of recombinant GH (rGH) was demonstrated to increase myocardial mass and reduce the size of the left ventricular chamber, resulting in improved haemodynamics, myocardial energy metabolism and clinical status.