POLYGRAPHIC ANALYSIS OF THE LEFT VENTRICULAR FUNCTION AND SYSTOLIC TIME INTERVALS IN CASES OF BUNDLE-BRANCH BLOCKS
Polygraphic analyses were carried out on the left ventricular function and systolic time intervals in patients with various types of bundle-branch blocks. The subjects were consisted of 31 cases with complete right bundle-branch block (CRBBB), 14 with CRBBB+left axis deviation (LAD), 18 with complete left bundle-branch block (CLBBB), and 2 with intermittent CRBBB. A decrease of the left ventricular function in the descending order of those with CLBBB, CRBBB+LAD, and CRBBB was found. In the CRBBB group the left ventricular function was directly dependent upon the severity of the basic disease. In the first two groups, however, in addition to the basic disease the left intraventricular conduction disturbance itself also seemed to affect the left ventricular function. As for the left ventricular systolic time intervals in the first two groups the beginning of the left ventricular ejection was delayed, and such a delay was especially marked in those with CLBBB. The delay in the beginning of the left ventricular ejection in those with CRBBB+LAD was mostly due to a prolongation of the isovolumic contraction time (ICT), while in those with CLBBB was mostly due to a prolongation in both electromechanical interval (Q-C) and ICT.