Q- versus non-Q-wave myocardial infarction: clinical characteristics and 6-month prognosis

A prospective study of 208 consecutive survivors of acute myocardial infarction was undertaken to determine the differences between Q- and non-Q-wave infarction, concerning data from the history, clinical course, and 6-month follow-up. There were 177 patients with Q-wave infarction and 31 patients with non-Q-wave infarction. There were no significant differences for the following variables: age, sex, diabetes mellitus, smoking, positive family history, hypertension, obesity, previous infarction, history of unstable angina, heart failure or chronic obstructive pulmonary disease (COPD), Killip class in the Coronary Care Unit (CCU), arrhythmias and conduction defects in the CCU as well as drugs used. Patients with non-Q wave infarction had a higher incidence of stable angina before the myocardial infarction and a lower value of creatine kinase (CK) and serum glutamic oxalacetic transferase (SGOT). During the 6-month follow-up, 9 cardiac deaths and 17 reinfarctions occurred, while 74 patients presented angina. There were no differences between the two groups concerning the incidence of cardiac death or angina, but patients with non-Q-wave infarction had a higher incidence of reinfarction at 6 months (p less than 0.001). We conclude that although patients with non-Q-wave myocardial infarction have a lesser degree of myocardial damage, they have a high incidence of early reinfarction which puts them in a high-risk group.