Coronary heart disease in residents of Rochester, Minnesota. VI. Hospital and posthospital course of patients with transmural and subendocardial myocardial infarction.

Abstract

During the period 1960 through 1979, 1,221 residents of Rochester, Minnesota, who were 30 years of age or older had a myocardial infarction as the first manifestation of coronary heart disease. Patients who had a prior diagnosis of congestive heart failure or valvular heart disease were excluded from this study. Of the 1,221 patients, 784 had a transmural infarction, 353 had a subendocardial infarction, and 84 had infarctions that could not be classified (most of the unclassified infarctions were associated with sudden death in patients who were not hospitalized). The age- and sex-adjusted 30-day case fatality rate was 18% among those with transmural and 9% among those with subendocardial myocardial infarction. No significant difference was found in subsequent survivorship or in net survivorship free of reinfarction during the first 5 years of follow-up. Five-year net survivorship free of reinfarction, coronary artery bypass operation, and cardiac death was not significantly different between the two groups, nor was net survivorship free of five established events (the three aforementioned events plus the development of congestive heart failure or angina). When these five events were considered independently in the two infarction cohorts, however, development of congestive heart failure was more common among patients with transmural infarction (P less than 0.01), whereas the development of angina was more common among patients with subendocardial myocardial infarction (P less than or equal to 0.06).