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)