Clinical, functional, and angiographic distinctions between Q wave and non-Q wave myocardial infarction: evidence of spontaneous reperfusion and implications for intervention trials.

We prospectively evaluated 241 consecutive patients with creatine kinase (MB fraction)-confirmed acute myocardial infarction with predischarge quantitative thallium-201 scintigraphy, coronary angiography, radionuclide ventriculography, and 24 hr Holter monitoring. Based on serial electrocardiograms, 154 patients had Q wave (QMI) and 87 had non-Q wave (NQMI) infarction. Despite less myocardial necrosis and better left ventricular function, the NQMI group had the same long-term survival as the QMI group. During 27 months of follow-up, patients with NQMI experienced more reinfarctions (p = .009), had a higher rate of unstable angina pectoris requiring rehospitalization (p = .034), and had a greater likelihood of subsequent bypass surgery or angioplasty (p = .018). Based on our thallium scintigraphic data, the greater clinical instability after NQMI appeared to be related to the presence of a larger residual mass of viable but jeopardized myocardium within the perfusion zone of the infarct-related vessel. Our results also indicate that the pathogenesis of NQMI may involve early spontaneous reperfusion and that patients with NQMI can experience sudden death despite well-preserved left ventricular function.