UNLABELLED: The contradictory views on long term clinical course of patients after non-Q wave myocardial infarction (NQMI) as compared with those after Q wave myocardial infarction (QMI)--induced us to undertake a comparative study of both types of myocardial infarction during a 8 year follow-up. The study was carried out in 400 patients (pts) with NQMI (mean age 51) and 485 pts with QMI (mean age 53). Both groups were compared. We have analysed the following parameters: the dynamics of ischaemic heart disease (unstable angina, reinfarction, arrhythmias, mortality) and coronary arteriography. During 8 year observation unstable angina and arrhythmias, were statistically more frequent in pts after NQMI. Recurrent myocardial infarction occurred in 196 (49%) of pts after NQMI and only in 87 pts (18%) after QMI (p less than 0.001). However, the difference in mortality between both groups was not significant (37% vs 39% respectively). Coronary angiography was performed at 1-6 months after myocardial infarction. In 65% of pts after NQMI detected lesions were limited to proximal part of one or two coronary arteries. CONCLUSION: NQMI is characterized by unstable long-term clinical course, and that is why pts with NQMI should be recommended for early coronary angiography and revascularization.