Physical Examination Video Series Video Lecture Course. Clinical skills. To understand Splitting of S2 better, we should first understand its normal physiology. Second heart sound: It has two audible components, the aortic valve closure sound (A2) and the pulmonic valve closure sound (P2), which are normally split on inspiration and virtually single on expiration. Technique: It has two audible components, the aortic closure sound (A2) and the pulmonic closure sound (P2), which must be separated by more than 20 msec (0.20 sec) in order to be differentiated and heard as two distinct sounds.
Splitting is best identified in the second or third left ICS, since the softer P2 normally is confined to that area, whereas the louder A2 is heard over the entire precordium, including the apex. Physiology: Various research findings suggests that closure of the aortic and pulmonic valves initiates the series of events that produces the second heart sound. In order to understand splitting of the second heart sound, knowledge of its relationship to the cardiac cycle is essential. Multimedia. Osce Exams Live. Physical Examination Video Series Video Lecture Course.