Effect of posture on the dynamics of left-ventricular contraction in healthy men with different degrees of physical fitness
Markiewicz, K.; Cholewa, M.
Kardiologia Polska 23(8): 683-690
1980
ISSN/ISBN: 0022-9032 PMID: 7420835 Document Number: 162958
In 50 cyclists after completion of a training period (I) and in 60 medical students not participating in any sports (II) the dynamics of left ventricular contraction was studied in lying (L) and in sitting (S) positions. Synchronous records were taken of ECG from the II lead, phonocardiogram from Erb's point and right carotid sphygmogram. Left ventricular contraction periods were calculated from the polycardiograms by Weissler's method. In the sitting position in both groups a reduction was observed in the indices of total electromechanical contraction (QS2I), mechanical contraction (S1S2I) and left ventricular ejection time (LVET), with prolongation of the pre-ejection period (PEP), isometric contraction (ICT) time and QS1 time. The PEP/LVET index increased compared to the values obtained in recumbent position. In the group of trained sportsmen the values of QS2I and S1S2I decreased significantly less than in the untrained subjects. The PEP and ICT times increased more significantly. The correlation between QS2, S1S2, LVET and the heart rate decreased in sitting position and was lower in sportsmen than in subjects with low physical activity.