MENTAL STRESS-INDUCED MYOCARDIAL-ISCHEMIA AND CARDIAC EVENTS

Objective.-To assess the clinical significance of mental stress-induce d myocardial ischemia in patients with coronary artery disease (CAD). Design and Setting.-Cohort study in outpatients in a tertiary care tea ching hospital assessed at baseline and followed up for up to 5 years. Subjects.-A total of 126 volunteer patients (112 men, 14 women; mean age, 59 years) with documented CAD and exercise-induced myocardial isc hemia. Outcome Measures.-Patients underwent baseline mental stress and exercise testing using radionuclide ventriculography and 48-hour Holt er monitoring. Patients were subsequently contacted by mailed question naires or telephone to document cardiac events, including death, nonfa tal myocardial infarction, and cardiac revascularization procedures, L ogistic regression and Cox proportional hazards models were used to ex amine the prognostic value of the ischemic measures after adjusting fo r such potential confounding factors as age, baseline left ventricular ejection fraction (LVEF), and history of myocardial infarction. Resul ts.-Twenty-eight patients (22%) experienced at least 1 cardiac event, Baseline mental stress-induced ischemia was associated with significan tly higher rates of subsequent cardiac events (odds ratio, 2.8; 95% co nfidence interval [CI], 1.0-7.7; P<.05), The LVEF change during mental stress was significantly related to event-free survival (risk ratio [ RR], 2.4; 95% CI, 1.12-5.14; P=.02), controlling for age, history of p rior myocardial infarction, and baseline LVEF. This relationship remai ned significant after controlling for electrocardiogram (ECG)-defined ischemia during exercise (RR, 2.2; 95% CI, 1.01-4.81; P<.05). The RR f or EGG-defined ischemia during exercise testing was 1,9 (95% CI, 0.95- 3.96; P=.07) and the RR for ambulatory ECG ischemia was 0.75 (95% CI, 0.35-1.64; P=.47). Conclusions.-The presence of mental stress-induced ischemia is associated with significantly higher rates of subsequent f atal and nonfatal cardiac events, independent of age, baseline LVEF, a nd previous myocardial infarction, and predicted events over and above exercise-induced ischemia, These data suggest that the relationship b etween psychological stress and adverse cardiac events may be mediated by the occurrence of myocardial ischemia.