Effect of training on left ventricular contraction dynamics at rest and during maximal exercise

Left ventricular contraction parameters were determined in sitting position in 21 road cyclists before and after a six-month training course at rest and after maximal exercise. For assessing the contractility of the heart synchronous records were obtained of the second ECG lead, phonocardiogram at Erb's point and right carotid sphygmogram. The polycardiograms were analysed by the method of Weissler. After completion of training the correlation between the total electromechanical systole (QS2) and the left-ventricular ejection time (LVET), on the one hand, and the heart rate, on the other hand, was less pronounced. Moreover, the total electromechanical systole index (QS2I) and the left-ventricular ejection time index (LVETI) were significantly (p less than 0.001) smaller, and the pre-ejection period (PEP) and the PEP/LVET ratio were significantly (p less than 0.05) greater than before the training course. During maximal exercise in both investigations the values of QS2I, LVETI, PEP, PEP/LVET ratio and isometric contraction time (ICT) were reduced (p less than 0.001). After the training PEP and PEP/LVET decreased more (p less than 0.05) than before training. The obtained results point to a greater functional reserve of the heart at rest, greater myocardial contractility during exercise, and lower decrease of stroke volume during exercise to exhaustion after 6 months of training than before training in relation to the values of these parameters before training in the same subjects.