Laser apexcardiogram in healthy young men: a comparative study with the conventional method.
Laser displacement technique is a new method to registrate the low frequency precordial movements. In 16 young healthy men the apexcardiograms were obtained subsequently by conventional way and by laser displacement technique. The basic differences in time intervals and amplitude relations were analyzed with paired t-test. On the laser apexcardiogram the peak of the positive deflection generated by ventricular systole came later (p less than 0.001), the proportion of the positive deflection to the total deflection was smaller (p less than 0.01) and the positive deflection elicited by atrial contraction was proportionally larger (p less than 0.05) than on the conventional apexcardiogram. The timing of the onset of systolic positive deflection and of the nadir of diastolic negative deflection were similar in both apexcardiograms. The observed differences are the consequences of the different physical basis of the two methods. The laser apexcardiogram seems to be more sensitive on the diastolic events and permits a better analysis of diastolic phenomena of the curve, including the atrial contraction.