Background—We studied the effects of recombinant growth hormone (rhGH) on exercise capacity and cardiac function in patients with ischemic cardiomyopathy.
Methods and Results—Seven patients (aged 55±9 years) with mild to moderate congestive heart failure (ejection fraction 31±4%) who were on standard therapy were included. The patients were studied at baseline, after 3 months of rhGH treatment, and 3 months after rhGH discontinuation. Cardiac function was assessed by exercise capacity, right heart catheterization at rest and after submaximal exercise, MRI, echocardiography, and Holter monitoring. When administered at a dose of 2 IU/d, rhGH doubled the serum concentration of insulin-like growth factor-I. rhGH improved clinical symptoms and exercise capacity significantly (New York Heart Association class 2.4±0.5 initially versus 1.4±0.5 at 3 months [mean±SD], P<0.05; O2max 13.6±3.8 versus 17.4±5.4 mL · kg-1 · min-1, P<0.05). Additionally, pulmonary capillary wedge pressures at rest and after submaximal exercise were reduced significantly. Cardiac output increased, particularly at rest (5.0±1.1 versus 5.8±1.3 L/min; P<0.05). Posterior wall thickness was increased (1.08±0.1 versus 1.24±0.3 cm; P<0.05), and the end-diastolic and end-systolic volume indexes decreased significantly after rhGH treatment. There was no significant increase in left ventricular ejection fraction. The improvements were partially reversed 3 months after rhGH discontinuation.
Conclusions—The administration of rhGH for 3 months in patients with ischemic cardiomyopathy results in significant improvement in hemodynamics and clinical function. The attenuation of left ventricular remodeling persisted 3 months after discontinuation of treatment.