Normally A2 precedes P2 and splitting increases with inspiration; abnormalities include:
- Widened splitting: Right bundle branch block, PS, mitral regurgitation
- Fixed splitting (no respiratory change in splitting): Atrial septal defect
- Narrow splitting: Pulmonary hypertension
- Paradoxical splitting (splitting narrows with inspiration): Aortic stenosis, left bundle branch block, heart failure
- Loud A2: Systemic hypertension
- Soft A2: Aortic stenosis (AS)
- Loud P2: Pulmonary arterial hypertension
- Soft P2: Pulmonic stenosis (PS)