Splitting of heart sounds from ventricular asynchrony in bundle-branch block, ventricular ectopic beats, and artificial pacing.

Asynchrony of ventricular contraction causes splitting of the first and second heart sounds which can be detected clinically in most normal subjects, and deviations from normal due to electrical or mechanical delays on one or other side of the heart have received much attention as valuable physical signs and in the understanding of hxmodynamics.