Limitations of exercise testing to screen cardiac patients for early nonmonitored rehabilitation exercise programs

To evaluate whether exercise testing might identify cardiac patients who do not require continuous electrocardiographic (ECG) monitoring during early rehabilitation exercise programs, 202 subjects (88 post-myocardial infarction [MI] patients and 114 post-coronary artery bypass graft surgery [;CABGS] patients) were studied. Symptom-limited exercise tests were obtained 3.9 ± 1.2 weeks after MI and CABGS. After the exercise test, all patients entered a ten-week continuous ECG-monitored exercise program. During the program, 19% of MI patients and 18% of CABGS patients developed serious ECG abnormalities while exercising. Among MI patients, the prevalences of an abnormal ECG during the program were 63% in patients with exercise-induced complex ventricular arrhythmias, 44% in patients with exercise-induced ST-segment depression, and 29% in patients with exercise-induced angina. Among CABGS patients, the prevalences of an abnormal ECG during the exercise program were 44% in patients with exercise-induced complex ventricular arrhythmias, 27% in patients receiving antiarrhythmic medications, and 24% in patients with less than a 5-MET exercise capacity during the exercise test. The data suggest that exercise testing can be useful in identifying patients who will exhibit an abnormal ECG during early cardiac exercise programs. However, since exercise testing was only able to identify 70% of MI and CABGS patients who developed an abnormal ECG during their exercise program, the results also suggest the necessity for providing continuous ECG monitoring for patients during early cardiac rehabilitation exercise programs.