Three distinct forms of rupture of the heart may be identified after myocardial infarction: sudden rupture with massive intrapericardial haemorrhage, and sudden death with clinical signs of electromechanical dissociation; rupture into the pericardium resulting in a false aneurysm, the treatment of which is surgical; subacute rupture which accounts for 30% of cases in which bleeding into the pericardium is slow and/or repeated. Over an 8 year period and in a series of 2,400 consecutive infarcts admitted to the intensive care unit, 10 cases of subacute rupture of the heart were diagnosed. They were 6 men and 4 women, with a mean age of 73.6 years. The clinical presentation was isolated chest pain in 5 cases, syncope alone in 2 cases and the association of pain and syncope in 3 cases. Six patients were in shock on admission. In two cases, shock developed after admission. The infarction was confirmed biologically by a significant elevation of creatinine kinase in 9 out of 10 cases. Transmural infarction was observed in 9 cases: the infarct was electrocardiographically non-transmural in 1 case. Emergency echocardiography showed pericardial effusion in all cases, usually moderate, but sometimes compressive with an intrapericardial echogenic mass suggesting a thrombus. Haemodynamic improvement was obtained by medication allowing cardiac catheterisation which showed adiastole in 3 cases. Coronary angiography was performed in 7 cases. In 5 of the 7 cases, apart from occlusion of the artery presumed to be responsible for the infarct, the coronary vessels were diffusely infiltrated without significant stenosis. Left ventriculography was performed in 7 cases. In 6 of the 7 cases regional akinesis was demonstrated: the 7th case showed dyskinesia of the anterior wall. In two cases, contrast medium was observed to fill the pericardium during ventriculography, indicating myocardial rupture. The diagnosis of subacute rupture, suggested by clinical and paraclinical (particularly echocardiography), was confirmed in 9 cases at surgery and in the 10th case at autopsy. Surgery consisted of repairing the rupture. In the last two cases, biological glue was used to reinforce the surgical repair. The clinical outcome was good after surgery in 6 cases with a follow-up of 5 months to 8 years. The diagnosis of subacute rupture should therefore be made on clinical and echocardiographic criteria, as these results suggest that surgery is often possible, with a good prognosis.