Dynamic exercise is the usual method for evaluating reserve cardiac function. Patients generally exercise in the upright position using a treadmill or sitting up (or in the supine position) using a bicycle ergometer.
Studies during dynamic exercise have evaluated ECG changes, the pattern of myocardial perfusion with thallium 201, and regional and global left ventricular function with radionuclide ventriculography. The most frequent diagnostic indication for these studies has been to detect coronary artery disease. The incorporation of scintigraphic techniques has enhanced the clinician's ability to make diagnoses more accurate than by exercise ECG alone.1,2
Dynamic exercise with leg muscles cannot be adequately performed by patients with peripheral vascular disease or neuromuscular skeletal disorders. In other patients, such as those with chronic obstructive lung disease or those who are only slightly motivated, dynamic exercise studies may fail to pick up diagnostic hemodynamic abnormalities. Finally, some investigators3 have suggested that