[Effect of ventricular filling volume on the R-amplitude in the ECG]

Among others as cause of the sigma R-amplitude in the ECG changes of the ventricular filling and the stroke volume, respectively, the sympathetic tone and the coronary blood supply are discussed. Patients with absolute arrhythmia in atrial fibrillation as well as patients with extrasystoles represent model examples, in whom of the three factors mentioned above only the stroke volume is changed. Measurements of the sigma R-amplitude as well as of the Einthoven/Goldberger leads as well as of the Wilson leads on the same patient showed higher sigma R-values for the heart beats which were preceded by a short diastolic filling phase (rapid phase of the absolute arrhythmia, interpolated extrasystoles) than in the heart beats with previous long diastolic filling time (slow form of the absolute arrhythmia, extrasystole with compensatory interval). The findings considerably change in their size from patient to patient, however, they are statistically to be ascertained in their tendency. In the practical valuation deviations of the sigma R-amplitude values which do not correspond to this relation should be referred to other determinants of the R-amplitude.