[Systolic intervals in disorders of intraventricular conduction]

The duration of the systolic intervals in 50 patients was studied. They were divided into the following groups of 10 each: 1) with normal intraventricular conduction; 2) with advanced right bundle branch block; 3) with advanced left bundle branch block; 4) with left anterior fascicular block, and 5) endocardial pacemaker in the right ventricle. The systolic intervals do not suffer modification in the presence of a right bundle branch block or a left anterior fasicular block. The left bundle branch block produces changes fundamentally in the preejection period at the expense of its two components. There also exists elevation of the systolic quotient. If the results obtained in various studies in the same patient are compared, it is possible to follow the evolution of ventricular alteration, but it is not valid, to make a comparison with the ideal values obtained in subjects with normal conduction. For those patients with a pacemaker in the right ventricular endocardium, the same criteria are applied as for the left bundle branch block. The shortening of the ejection period suggests a decrease in the volume of ventricular ejection.