- Jun 18, 2022
- 1 min read
Updated: Jul 29, 2023
Physiological Splitting of Second Heart Sound
Components of Second Heart Sound
Second heart sound (S2) is produced due to the closure of semilunar valves.
Semilunar valves include:
Aortic valve: between the left ventricle and aorta
Pulmonary valve: between the right ventricle and pulmonary artery
So actually there are two components of second heart sound:
Aortic component (A2)
Pulmonary component (P2)
The Mechanism of Splitting
Pressure in the aorta is higher than that in the pulmonary artery
↓
The aortic valve closes slightly before the closure of the pulmonary valve
↓
The sound of closure of the aortic valve is produced a bit earlier than that of the pulmonary valve
↓
Splitting of S2 into A2 and P2 components
Accentuation of Splitting During Deep Inspiration
Deep inspiration
↓
Intrathoracic pressure becomes more negative
↓
Venous return to the right heart increases as compared to that in the left heart
↓
Emptying of the right ventricle takes a little longer than the left ventricle
↓
Closure of pulmonary valve is delayed
↓
Accentuation of splitting of second heart sound
Comments