Greater diagnostic sensitivity of treadmill versus cycle exercise testing of asymptomatic men with coronary artery disease.

Maximal hemodynamic and ventilatory responses using cycle and treadmill ergometer were compared in 52 asymptomatic patients with angiographically proved coronary artery disease. Moreover, test sensitivity with respect to ST-segment depression and typical angina pectoris were compared between exercise modes used. Exercise tests were performed on different days in randomized order. In 42 patients, exercise-induced myocardial ischemia, expressed as a fraction of left ventricular circumference, was assessed by thallium-201 scintigraphy. The main finding of this study was a significantly higher maximal oxygen uptake (1.87 +/- 0.4 vs 2.2 +/- 0.5 liters/min; p less than 0.001), heart rate (148 +/- 19 vs 158 +/- 18 beats/min; p less than 0.001) and rate-pressure product (28.3 +/- 5 x 10(3) vs 30.7 +/- 5 x 10(3); p less than 0.001) during treadmill walking than during cycling. Therefore, stress-induced myocardial ischemia was significantly more extensive after treadmill walking (31 +/- 37 degrees vs 45 +/- 40 degrees; p less than 0.001). Moreover, there were significantly more patients with signs of myocardial ischemia (ST-segment depression or typical angina pectoris, or both) during treadmill than during cycle ergometry (35 vs 25 patients; p less than 0.05). However, lactate levels measured at peak exercise (4.07 +/- 2.0 vs 4.38 +/- 1.9 mmol/liter) and 3 minutes into the recovery period (5.60 +/- 2.2 vs 5.80 +/- 2.2 mmol/liter) were comparable between both methods, indicating no significant difference in anaerobic energy production. These findings suggest that walking on a treadmill represents an exercise method with a greater ability than cycling to detect coronary artery disease.