Question

which of the following is false related to the splitting of the s2 heart sound?
physiologic splitting occurs when the aortic valve closes before the pulmonic valve during inspiration
paradoxical splitting occurs when the aortic valve closure follows the pulmonary closure
in a normal heart, s2 is usually split during expiration
wide splitting can occur a delay of the pulmonic valve closure

Explanation:

• Physiologic splitting: During inspiration, increased venous return to the right side of the heart delays pulmonic valve closure, so aortic valve closes before pulmonic valve - this is correct.
• Paradoxical splitting: Occurs when aortic valve closure is delayed (e.g., in left bundle branch block) and follows pulmonic closure - this is correct.
• Wide splitting: Can occur with delay in pulmonic valve closure (e.g., right bundle branch block) - this is correct.
• In a normal heart, S2 is usually single during expiration (due to more similar pressures in aorta and pulmonary artery causing simultaneous valve closure) and split during inspiration.

Answer:

In a normal heart, S2 is usually split during expiration.