Reversible dilated cardiomyopathy due to growth hormone deficiency.

An unusual case of severe dilated cardiomyopathy is described in a woman with postpartum hypopituitary function, which was characterized by marked decrease of cardiac myofibrils (decreased ratio of myofibrillar volume:cell volume) and somatomedin C deficiency. The patient was treated with a daily intramuscular dose of 4 UI of recombinant human growth hormone for 3 months. Clinical and laboratory assessment and follow-up consisted of noninvasive (echocardiograms, Doppler study, and clinical laboratory tests) and invasive procedures (angiography and endomyocardial biopsy). Morphologic study included optical and electron microscopic examinations and morphometric analysis. The patient exhibited a relevant improvement of cardiac function after recombinant human growth hormone administration. The clinical improvement was confirmed by normalization of electrocardiographic voltages, increased myocardial mass, angiography, and optical and electron microscopic examination, which showed a dramatic recovery of myofibrillar content in myocardiocytes. Furthermore, withdrawal of growth hormone was followed by reduction of electrocardiographic voltages and myocardial mass as well as by impairment of left ventricular function. The authors suggest that there are forms of dilated cardiomyopathy that may benefit dramatically by growth hormone administration. These forms should be identified by growth hormone/somatomedin C axis deficiency and by decrease in myofibrillar content at endomyocardial biopsy.