Which of the following is an abnormal heart sound?

• A. Ejection click
• B. Friction rub is a normal heart sound
• C. A normal heart sound
• D. Systolic murmur

Answer: (A)

An abnormal extra heart sound can come from valve mechanics, and the ejection click is a classic example. It’s a brief, high-pitched sound heard early in systole, right after S1, produced when a semilunar valve (usually the aortic or pulmonary valve) opens abruptly against a stiff or edematous opening. This sound points to valvular abnormality, such as a bicuspid aortic valve or residual stenosis, and it has a characteristic timing that helps distinguish it from normal S1/S2 sounds.

Other options describe sounds that are not normal: a normal heart sound would not be an extra sound, and a systolic murmur is also abnormal, though of a different type. A friction rub is indeed abnormal, signaling pericarditis, but the ejection click is the prototypical discrete abnormal systolic sound associated with valve opening, which is why it’s identified as the abnormal heart sound in this context.