[Heart diagnosis using M-mode echocardiography. Continuing registration of transverse left ventricular inner diameters. I. Measurement in healthy persons]

Transversal internal diameters of the left ventricle can be determined simply, quickly, precisely and continuously by external application of impulse reflected ultrasound. These measurements permit the calculation of "relative cross-sectional area differences" between end-diastole and end-systole (RCD); peak and mean velocity of circumferential fiber contraction can be equally determined. The present report gives an analysis of 133 measurements on 81 healthy individuals. All persons were examined at rest, a part of them during exercise. All measurements were taken while supine position. The transversal internal diameters averaged 4.9 cm with considerable standard deviations. There was only a trend showing diminution of diameters during exercise. The "relative cross-sectional area differences" (RCD) between end-diastole and end-systole have only small standard deviations compared with the diameters. The average 58.3% and show a slight increase during exercise. The RCD were only slightly influenced by heart rate at rest. In contrast, peak and mean velocity of circumferential fiber contraction are obviously dependent on the heart rate. The results indicate a linear correlation between mean velocity and heart rate. The "relative mean velocities of contraction" (RVC), defined by normalization of the values to a rate of 60/min, average 1.0 and have small standard deviations like the RCD. The small physiological variety and the excellent reproducibility of data offer RCD and RVC determined by echocardiography as sensitive dynamic heart parameters applicable in clinical cardial diagnosis without any stress for the patient.