Most common cause of single S2 – Cardiology MCQ – Answer
Most common cause of single second heart sound (S2) – Correct answer: d) Inaudibility of pulmonary component (P2) due to increased anteroposterior diameter of chest in older adults
Other causes are absence of pulmonary component or aortic component.
Absent P2: Pulmonary atresia, severe valvar pulmonary stenosis
Absent A2; Aortic atresia, severe aortic stenosis
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Reference: Braunwald’s Heart Disease: A Textbook of Cardiovascular Medicine, 10th Edition. Chapter 8: Physical Examination of the Heart and Circulation