Abnormal electrocardiographic responses to exercise in patients referred for noninvasive evaluation of occlusive peripheral arterial disease

Abstract

Fifty consecutive patients were referred to the noninvasive laboratory for evaluation of suspected peripheral vascular disease. There were 30 men and 20 women aged 27 to 88 years (mean 63). Measurement of cardiovascular risk factors revealed the following distributions: cigarette smoking 90 percent, hypertension 28 percent, diabetes mellitus 22 percent and hyperlipidemia 6 percent. Eight patients had a history of angina pectoris, 7 a prior myocardial infarction, 5 a cerebrovascular accident and 11 prior peripheral arterial revascularizatlon surgery. Evaluation detected 32 patients (64 percent) with occlusive arterial disease of the lower limbs. Lead II of the electrocardiogram was monitored during and 1, 2, 3, 4, and 5 minutes after treadmill exercise with a limiting grade of 10 percent at 2.5 miles/hour. The mean resting and maximal heart rates for the study group were, respectively, 78 and 106 beats/min. The average treadmill speed attained was 1.9 miles/hour at a mean duration of 3.8 minutes. Thirty-seven subjects (74 percent) had normal electrocardiographic responses to exercise. Of 13 patients (26 percent) with an abnormal exercise electrocardiogram, 7 had possible ischemic S-T segment responses. Six subjects manifested frequent premature ventricular complexes during exercise. Four other patients had abnormal S-T segments in the resting electrocardiogram (two had a pattern of left bundle branch block, and two a pattern of left ventricular hypertrophy and strain). A survey of 60 peripheral vascular laboratories in the United States revealed that only 29 percent of the responding 34 centers routinely performed electrocardiographic monitoring during exercise testing. It is concluded that (1) electrocardiographic monitoring during exercise in the peripheral vascular laboratory can provide useful information regarding S-T segment responses, (2) abnormal S-T segment responses in patients with suspected peripheral vascular disease are frequently manifested at low levels of work load, and (3) such routine monitoring should be performed for patient safety.