Characterization and prognostic significance of silent myocardial ischemia on predischarge electrocardiographic monitoring in unselected patients with myocardial infarction.

Characteristics and prognostic significance of ischemic ST changes at predischarge Holter monitoring were evaluated in 270 consecutive postinfarction patients. The 64 patients with ST changes had a greater incidence of non-Q-wave myocardial infarction (p less than 0.01) and ventricular premature contractions (p less than 0.01); they were more frequently in Moss class greater than 2 (p less than 0.01) and they had a lower wall motion score (p less than 0.05). At 2-year follow-up, patients with ST changes had a higher incidence of cardiac death and reinfarction. At multivariate analysis, Killip class (p less than 0.01) and ST changes (p less than 0.05) were the most predictive variables; when multivariate analysis was repeated including an additional variable--the inability to perform a stress test--Killip class was the most significant variable (p less than 0.01), and the presence of ST changes showed only borderline statistical significance (p less than 0.1). In the subset of patients who did not perform the stress test, ST change was the most important variable (p less than 0.01), followed by Killip class (p less than 0.05). Thus, after myocardial infarction, ST changes during Holter monitoring are associated with a poor prognosis and appear useful for stratifying patients who do not perform exercise stress tests.