The aim of this study was to assess the effects a long-acting somatostatin analogue (octreotide) had on the heart function of acromegalic patients. Five patients fulfilling clinical criteria of active acromegaly without symptoms of heart dysfunction, were treated with increased doses of octreotide (300, 600, 900, 1,200 and 1,500 micrograms/daily) over a period of six months. Growth hormone (GH) profiles were carried out during each different dose of octreotide. M-Mode, two dimensional and Doppler echocardiographic evaluation were performed both before and after treatment. Although the GH levels of all patients dropped after each increment of the octreotide, the responses were not homogeneous. Six months after the onset of treatment, echocardiographic studies revealed a significant reduction in the interventricular septum thickness (IVST) (p less than 0.05) and Doppler analyses showed an increase in the early diastolic transmitral flow velocity (p less than 0.05). Our results indicate that octreotide is capable of reversing acromegalic cardiopathy, since it not only reduces GH levels to within normal limits but improves left ventricular hypertrophy and distensibility without modifying contractility.