The authors report the case of a patient with acromegaly. The clinical history was dominated by left ventricular failure, for which acromegaly was the only evident cause. The cardiac index, pulmonary arterial pressure and the average pulmonary capillary pressure were measured before ablation of the hypophyseal tumour; the measurements were repeated 3 months and 8 years later. The postoperative course followed two phases: transient improvement of the haemodynamic parameters, then relapse of cardiac failure. This case confirms the possibility of a true cardiomyopathy during acromegaly; but the fact that the cardiac failure did not regress despite the decreased growth hormone levels was unusual and raises several physiopathological hypotheses.