[Exercise tolerance of patients with artificial cardiac pacemakers (author's transl)].

In order to determine their exercise tolerance, 20 patients with artificial ventricular demand pacemakers below the age of seventy were studied by bicycle ergometry. Only 30% of the patients showed a normal exercise tolerance according to the criteria by Kaltenbach, while 70% stopped the test prematurely because of leg fatigue, dyspnoe or chest pain. In terms of their exercise tolerance, there was no difference between patients who developed normal sinus rhythm or rapid atrial fibrillation during the exercise and those who remained at the fixed pacemaker rate throughout the test. It is concluded, therefore, that the exercise tolerance of pacemaker-patients is not only limited by the fixed heart rate but mainly by the underlying heart disease (coronary heart disease, cardiomyopathy, hypertensive heart disease etc.) and the general physical condition of the patients. In an age-matched control group of 20 patients 50% showed a normal exercise tolerance and the duration of exercise in this group was only slightly longer (21%) than in the pacemaker-group.