Myocardial infarction is an underestimated complication of disseminated lupus erythematosus (DLE). Its features, treatment and prognosis are poorly understood. From June 1988 to December 2002, out of 1572 consecutive patients admitted during the first hours of acute myocardial infarction with ST elevation, 7 (5 women, aged 38 +/- 7 years) had DLE. The commonest risk factor was smoking (N = 4). There was a higher incidence of anterior infarction (N = 5). The infarct occurred 7 +/- 5 years after diagnosis of DLE. There were other complications of DLE in all cases. Three patients had antiphospholipid syndromes. The culprit artery was usually the left anterior descending (N = 5). The lesions included stenosing atheroma (N = 5) and extensive thrombosis (N = 5). The coronary disease was usually limited to a single vessel (N = 5). Revascularisation procedures include pre-hospital thrombolysis (N = 3) followed by immediate angioplasty (N = 2) or primary angioplasty (N = 4). TIMI grade 3 flow was obtained in all cases, 278 +/- 162 min after the onset of symptoms. The clinical course was characterised by acute reocclusion in 3 patients, recurrent in 2 patients with an antiphospholipid syndrome, and death in 1 case. Acute myocardial infarction occurs in already complicated cases of DLE, in young patients, associating atherosclerosis and extensive thrombosis. The risk of early reocclusion after reperfusion is high, especially in cases with the antiphospholipid syndrome.