[Behavior of the R-amplitude in ergometric and pharmacologic stress in comparison with coronary morphologic findings in patients with coronary heart disease].

The cause of R-wave amplitude changes in the ECG under load remain unknown. One of the possible aetiological factors is myocardial ischaemia. The aim of the present study was to investigate possible relationships between amplitude changes and transient myocardial ischaemia. In this retrospective study, 89 patients (74 men, 15 women) were investigated. The results of exercise ECG, a dipyridamole test and coronary angiography were available for all patients participating. The patients were divided into four groups (group I: patients with relevant coronary stenosis [n = 46], group II: patients with no relevant coronary stenoses [n = 43], group III: patients with pathological results in all three procedures [n = 29], and group IV: patients with unremarkable findings in all three investigations [n = 14] and the R-wave amplitude changes in various phases of ergometry and dipyridamole provocation were measured. All four groups showed a significance decrease in R-wave amplitude at maximum provocation as compared with baseline values. A qualitative analysis of the amplitude changes indicated a tendency for them to be dependent on the severity of coronary stenosis. A quantitative analysis, however, revealed no significant correlations between the R-wave amplitude and ST segment changes or angiographic findings. This means that R-wave changes during an exercise ECG or a dipyridamole test do not permit us to distinguish between patients with or those without coronary artery stenosis. Changes in the R-wave amplitude observed under loading must be due to factors other than myocardial ischaemia.