The prognosis for patients with non-Q-wave myocardial infarction (MI) remains controversial, although a number of studies have shown a less favorable outlook after hospital discharge for patients with non-Q-wave than for those with Q-wave infarction. Numerous management strategies are available to the clinician, many of which involve an interventional strategy (myocardial revascularization with coronary bypass surgery or angioplasty) or a more conservative approach which emphasizes secondary prevention with medical therapy. This review summarizes the role of identifying risk variables in patients with non-Q-wave MI and their importance to clinical decision making. Based on data obtained from the Diltiazem Reinfarction Study (DRS), it has been shown that 20% of patients experience one or more episodes of spontaneous postinfarction angina which is associated with a significant increased (33%) 2-week mortality and an appreciable fivefold increased incidence of early reinfarction compared to patients without early recurrent ischemia. Similar findings have been observed in this same cohort of patients who were followed for one year, in that there was twofold higher incidence of death and late reinfarction at one year of follow-up. Other risk factors also appear to be important determinants of adverse long-term outcome after non-Q-wave MI and include persistent ST segment depression on serial electrocardiograms, congestive heart failure, and left ventricular hypertrophy. Medical therapy employed for secondary prophylaxis after non-Q-wave MI has failed to show a convincing therapeutic rationale for beta blocker administration. In contrast, diltiazem has been shown to influence the early and late outcome following non-Q-wave MI favorably.(ABSTRACT TRUNCATED AT 250 WORDS)