[Clinical significance of exercise-induced ST-segment elevation in lead aVR and V1 in patients with chronic stable angina pectoris and strongly positive exercise test results].

Electrocardiographic abnormalities in lead aVR and V1 are rarely analyzed on exercise electrocardiograms. Clinical significance of exercise-induced ST-segment changes in lead aVR and V1 during strongly positive electrocardiographic exercise test (EET) in patients with chronic stable angina pectoris remains unclear. The aim of the study was to assess the value of lead aVR and V1 on the exercise electrocardiogram for the detection of left main coronary artery stenosis (LMCAS) and its equivalent (LMCASE) in patients with chronic stable angina pectoris and the strongly positive EET result. The study group consisted of 118 consecutive patients (mean age 58.8 +/- 9.5 years, range 38-77 years), including 30 (25.4%) women. Patients were divided into three groups. In group I, 31 patients with ST elevation in lead aVR and V1, in group II 66 patients with isolated ST elevation in lead aVR, and in group III 21 patients without ST elevation in lead aVR, induced with exercise, were included. Coronary arteriography results were compared among these groups. In patients with isolated exercise-induced ST elevation in lead aVR, the prevalence of LMCAS was five times more frequent than in patients without lead aVR ST elevation (25.8% vs 4.8% p<0.05). There were no differences in the prevalence of LMCASE and multi-vessel coronary disease in the studied groups. In patients with LMCAS significant ST elevation in lead aVR during strongly positive EET were observed (0.25 +/- 0,4 mm vs 1.43 +/- 0.6 mm p = 0.003), whereas there were no significant exercise-induced electrocardiographic changes in lead V1 (0.61 +/- 0.6 mm vs 0.77 +/- 0.6 mm p = 0.08). Sensitivity of isolated exercise-induced ST elevation in lead aVR in detection of LMCAS was 85.0%, specificity - 50.0%, positive predictive value - 25.8%, negative predictive value - 94.2%, and total accuracy - 55.9%. Exercise-induced ST elevation in lead aVR on the strongly positive exercise ECG may detect LMCAS in patients with chronic stable angina pectoris.