[Dobutamine stress test. Specificity and sensitivity of continuous ST-segment monitoring in 12 simultaneous standard ECG leads]

This study was designed to evaluate the specificity and sensitivity of the dobutamine stress test with continuous ST-segment monitoring in 12 standard leads.

We analyzed 75 patients, 36 with unstable angina, 22 post-myocardial infarction angina, 3 after successful angioplasty, 6 chronic stable angina, and 8 atypical chest pain (with normal coronary arteries). All of them underwent coronary angiography (coronary lesions were considering significant with > 70%). Beta-blocking agents, calcium antagonists, and nitrates were discontinued for 48 h before the test. A 12-lead ECG was acquired automatically and ST-segment changes were monitored. Dobutamine infusion started at 5 microgram/kg/min and was increased at 3-minute intervals to 10 microgram, 20 microgram, and a maximum of 40 microgram/kg/min. If heart rate did not reach 85% of the theoretical maximum, 0.5-1 mg atropine was given without discontinuing dobutamine infusion.

Fifty patients (67%) had abnormal coronary arteries (excluding vessels with 100% obstruction) and 25 patients (33%) had normal arteries. In the group of patients with coronary lesions, the test was abnormal in 90% and normal in 10%. In the group of patients with normal arteries, the test was abnormal in 16% and normal in 84%. Consequently, the test had 90% sensitivity, 84% specificity, and 10% false negative and 16% false positive results.

Our results showed that the dobutamine/ECG test was a simple, effective, and safe bedside tool for diagnosing the severity of coronary disease.