ST segment elevation with exercise: a marker for poor ventricular function and poor prognosis. Coronary Artery Surgery Study (CASS) confirmation of Seattle Heart Watch results.

The functional and prognostic significance of exercise-induced ST elevation (by computer averaging) in ambulatory patients with coronary heart disease was recently reported for 181 patients in the Seattle Heart Watch (SHW). To further evaluate this, 3050 approximately similar patients enrolled in CASS were analyzed with respect to initial findings, survival, and incidence of secondary coronary events over the next 6 years. The ST elevation responses in CASS patients were classified by visual interpretation of 1 mm or more, whereas the SHW patients were identified by voltage greater than 0 mV. Accordingly, prevalence of exercise-induced ST elevation was lower in CASS patients, but they had greater frequencies of prior myocardial infarction and left ventricular enlargement and dysfunction. The poor survival was similar in the subgroup with ST elevation during exercise and recovery in CASS and SHW. Although not an independent predictor when invasive variables are known, ST elevation emerges as a useful predictor when exercise testing is performed before diagnostic invasive studies.