Bundle Branch Block and Its Hemodynamics in the Dog

Abstract

Electrocardiograms were recorded and hemodynamical measurements made in fifteen adult mongrel dogs with the main bundle branches blocked experimentally.
The electrocardiographical characteristics of the bundle branch blocks on both sides were the same in dogs as in man.
There was no difference im any hemodynamical measurement in the right bundle branch between the value before blocking and that after blocking. In the left bundle branch block, however, there was a decrease in the left intraventricular pressure, the systemic blood pressure, and the blood stream velocity in the peripheral artery. On the contrary, the right intraventricular pressure increased in this block. It was assumed that circulatory disturbances might have appeared in both systemic and pulmonary circulatory systems of the block continued chronically. From the alterations in the right intraventricular pressure curve in the left bundle branch block, it was presumed that the ventricular septum might have played an important role in the right ventricular output formation.