The extra volume in the right ventricle takes longer to eject, delaying P2.
Understanding the mechanics, timing, and variations of S2 is essential for diagnosing valvular disease, pulmonary hypertension, and congenital heart defects. 🩺 The Physiology of S2
Anything that further delays right ventricular emptying. 📍 How to Auscultate S2
A2 and P2 are separated enough to be heard as two distinct sounds. ⚠️ Abnormal S2 Findings
S2 is composed of two distinct components:
| Pattern | Definition | Key Auscultatory Features | Most Likely Diagnoses | | :--- | :--- | :--- | :--- | | | A2-P2 interval is abnormally wide and does not vary with respiration. | Split heard in both inspiration and expiration; no change in interval. | Atrial Septal Defect (ASD) (classic), Right bundle branch block (RBBB), severe pulmonary stenosis. | | Paradoxical (Reversed) Splitting | P2 occurs before A2; split widens during expiration and narrows during inspiration. | Split heard in expiration; inspiration causes fusion into a single sound. | Left bundle branch block (LBBB) , severe aortic stenosis, hypertrophic cardiomyopathy, right ventricular pacing. | | Wide Physiologic Splitting | Split is wider than normal but still varies with respiration (wider on inspiration). | Normal respiratory variation, but interval > 30-40 ms at the sternal edge. | RBBB (most common), pulmonary stenosis, mitral regurgitation, pulmonary embolism (acute). |
The S2 heart sound is caused by the closure of the aortic and pulmonary valves. The aortic valve closes when the pressure in the aorta exceeds the pressure in the left ventricle, while the pulmonary valve closes when the pressure in the pulmonary artery exceeds the pressure in the right ventricle.
The extra volume in the right ventricle takes longer to eject, delaying P2.
Understanding the mechanics, timing, and variations of S2 is essential for diagnosing valvular disease, pulmonary hypertension, and congenital heart defects. 🩺 The Physiology of S2
Anything that further delays right ventricular emptying. 📍 How to Auscultate S2
A2 and P2 are separated enough to be heard as two distinct sounds. ⚠️ Abnormal S2 Findings
S2 is composed of two distinct components:
| Pattern | Definition | Key Auscultatory Features | Most Likely Diagnoses | | :--- | :--- | :--- | :--- | | | A2-P2 interval is abnormally wide and does not vary with respiration. | Split heard in both inspiration and expiration; no change in interval. | Atrial Septal Defect (ASD) (classic), Right bundle branch block (RBBB), severe pulmonary stenosis. | | Paradoxical (Reversed) Splitting | P2 occurs before A2; split widens during expiration and narrows during inspiration. | Split heard in expiration; inspiration causes fusion into a single sound. | Left bundle branch block (LBBB) , severe aortic stenosis, hypertrophic cardiomyopathy, right ventricular pacing. | | Wide Physiologic Splitting | Split is wider than normal but still varies with respiration (wider on inspiration). | Normal respiratory variation, but interval > 30-40 ms at the sternal edge. | RBBB (most common), pulmonary stenosis, mitral regurgitation, pulmonary embolism (acute). |
The S2 heart sound is caused by the closure of the aortic and pulmonary valves. The aortic valve closes when the pressure in the aorta exceeds the pressure in the left ventricle, while the pulmonary valve closes when the pressure in the pulmonary artery exceeds the pressure in the right ventricle.