The authors report three cases of myocardial infarction in which an attempt at intra-coronary fibrinolysis in the acute phase was either transiently effective or totally ineffective. In these three cases, percutaneous endoluminal dilatation was possible allowing restoration of correct coronary flow. The place of percutaneous angioplasty is therefore discussed either immediately after fibrinolysis, when the risk of re-thrombosis appears to be greatest or perhaps in the absence of an attempt at clot lysis, when fibrinolytic treatment is contra-indicated.