Limitations of exercise testing in critical left coronary artery disease

Exercise testing was evaluated in 51 patients with critical left coronary artery disease (LCA) documented by coronary arteriography within two weeks of their bicycle ergometer (26 patients) or treadmill (25 patients) electrocardiographic study. Adequate tests, as defined by the patient having reached 85% of predicted maximum heart rate, were achieved in only 16 patients on the ergometer (62%) and in 21 (84%) on the treadmill. Nevertheless mean maximum double product (220 vs 232) and mean exercise time (4.6 min vs 5.0 min.) were similar (p:NS). The sensitivity for ergometry and treadmill testing was 75 and 62% respectively. If however we include those negative studies in which for various reasons patients were unable to achieve 85% of their predicted maximal heart rate (i.e., inadequate studies), sensitivity was only 46 and 52% respectively. Thus a sizable group of patients with critical LCA disease cannot adequately perform exercise tests especially on the ergometer; and over half of all such patients studied will be found for one reason or another to respond negatively, regardless of exercise protocol.