Murmur heard in aoic regurgitation is: September 2009
**Question:** Murmur heard in aortic regurgitation is:
A. Mitral regurgitation
B. Pulmonary regurgitation
C. Aortic stenosis
D. Tricuspid regurgitation
**Core Concept:**
Aortic regurgitation (AR) is a heart valve disorder where the aortic valve fails to close properly, allowing blood to flow back into the aorta from the left ventricle. This results in increased workload on the left ventricle and decreased blood flow to the peripheral circulation. A characteristic murmur may be heard in AR as it indicates abnormal blood flow.
**Why the Correct Answer is Right:**
The correct answer is D, tricuspid regurgitation (TR), because the murmur heard in aortic regurgitation is actually a result of TR. When TR occurs, the regurgitant blood flows retrograde (backward) into the right atrium (RA) and right ventricle (RV). This causes a turbulent flow, which produces the characteristic murmur heard in AR.
**Why Each Wrong Option is Incorrect:**
A. Mitral regurgitation (MR) is incorrect because it is not the source of the murmur heard in AR. MR occurs when the mitral valve fails to close properly, leading to regurgitation into the left atrium and left ventricle. The murmur associated with MR is a result of flow turbulence, not the cause of the murmur heard in AR.
B. Pulmonary regurgitation (PR) is incorrect because PR occurs when blood flows from the pulmonary artery into the pulmonary veins. This does not produce the murmur heard in AR.
C. Aortic stenosis (AS) is incorrect because AS is a condition where the aortic valve is narrowed, leading to decreased blood flow to the body. The murmur heard in AS is a result of increased pressure in the left ventricle and aortic root, not the cause of the murmur heard in AR.
**Clinical Pearl:**
The murmur heard in aortic regurgitation is a result of turbulent blood flow caused by tricuspid regurgitation (TR) into the right heart chambers (right atrium and right ventricle). This phenomenon is essential to understand as it helps differentiate between murmurs caused by different cardiac conditions. In AR, the focus is on assessing the heart murmur caused by TR, while in AS, AS, MR, and PR, the focus is on the underlying cardiac condition causing the murmur.