At medium term, the results of delayed angioplasty (DA) following intravenous thrombolysis (IVT) in terms of arterial permeability but particularly of left ventricular function (LVF) is still poorly understood and is the subject of this prospective study. Over 18 months, 76 patients underwent DA for the residual stenosis on day 8 +/- 5 with complete and partial success rates of 88.2% and 11.8% respectively. Rapid reocclusion (< 48 hours) was documented in 9.2% of cases. After 6 months, there had been no deaths and no recurrence of infarction but a recurrence of angina in 23.7% of cases. Angiographic monitoring, carried out in 56 cases (73.7%) after 6 +/- 2.4 months identified 21 restenosis (37.5%) and 6 re-occlusions (10.7%). 12 of the restenosis were successfully re-dilated. The effect on LV function was investigated in 50 patients. In the absence of reocclusion, the ejection fraction and the kinetics of the infarcted territory were improved; significant restenosis (> 60% by digital densitometry) did not appear to offset these improvements. In addition to the maintenance of arterial permeability, the possibility of functional recovery appears to be conditioned by the degree of contractile abnormality observed during the initial ventriculography. Despite the absence of restenosis after 6 months, the occurrence on day 6 of akinesia or above all of dyskinesia reduces the chances of contractile improvement with as a corollary more marked LV changes.