NEW YORK (Reuters Health) – Exercise-induced ST-segment elevation in patients who never had a myocardial infarction (MI) is a highly specific marker of coronary artery disease and a signal of severe stenosis, according to a report from Northern Ireland.

“If a chest pain patient is able to exercise and ST elevation occurs in any of the monitored leads in the absence of a previous myocardial infarction, then the patient is very likely to have a high grade stenosis in the artery subtending that ischemic area,” senior author Dr. Jennifer Adgey told Reuters Health.

Dr. Adgey and her colleagues at Royal Victoria Hospital in Belfast analyzed 14,941 exercise stress tests performed between 1998 and 2005 to assess chest pain in patients without a history of myocardial infarction. In cases with ST-segment elevation, the researchers obtained and reviewed medical records and corresponded with the patients’ general practitioners to determine outcomes.

In the November issue of Heart, the investigators report that 116 patients (0.78%) developed ST-segment elevation during exercise or in the recovery phase, and 108 underwent coronary angiography at the authors’ institution.

All patients who had angiography had at least one severe coronary artery stenosis (>70%). The site of ST-segment elevation on exercise electrocardiogram was 95.4% predictive of severe stenosis in the coronary artery that supplied that area.

Overall, 60 patients had single-vessel disease, and 48 had multi-vessel disease (two or more major vessels with at least 70% stenosis). On multivariate analysis, prolonged duration of ST-segment elevation was the only predictor of multi-vessel disease (odds ratio 1.097 per minute). The average duration of ST elevation was 4.4 minutes in patients with single vessel disease and 7.7 minutes with multi-vessel involvement.

Sixty seven patients underwent percutaneous coronary intervention (for the most part, simultaneously with angiography), and 31 underwent coronary artery bypass grafting at a median of 101 days after the angiogram.

With complete follow-up data available for 113 patients, the authors were able to determine that “the overall event rate was low.”

“The projected 7-year event-free survival probability was 62.1% for those undergoing coronary artery bypass grafting, 77.1% for those who had percutaneous coronary intervention, and 68.6% for those not undergoing revascularization,” the researchers report. “There was no significant difference between these three groups.”

When patients with no history of MI have ST elevation during exertion or during the recovery phase, “urgent coronary angiography should be considered as the majority will require revascularization for severe obstructive coronary artery disease,” the authors conclude.

Reference:
Heart 2009;95:1792-1797.