[R spike potentials in ergometric stress: patients with dilated cardiomyopathy in comparison to coronary heart disease].

R-wave amplitude changes during exercise were compared in patients with cardiomyopathy (n = 32), patients with coronary artery disease (n = 58) and controls (n = 12). Patients with cardiomyopathy (CMP) had a smaller R-wave amplitude (RWA) at rest than those with coronary artery disease (CAD). At comparable levels of exercise patients with CMP showed no change in RWA, while those with CAD demonstrated an increase in RWA. Controls showed a decline in RWA. In patients with CAD changes in RWA during exercise were more sensitive in the detection of disease than ST-segment changes. Left ventricular function was the major determinant of the direction and magnitude of RWA changes both in patients with CMP and CAD, with lesser changes in RWA in patients with more severely reduced left ventricular function.