---

This is a graphic example of paradoxic splitting.

One type of expiratory splitting is paradoxical splitting of the second heart sound. It occurs whenever the aortic closure is significantly delayed. During inspiration, the sounds fuse, as P2 is also delayed. During expiration, pulmonary closure precedes the delayed A2. Causes of paradoxical splitting include electrical and mechanical delays, such as left bundle branch block and aortic stenosis.