Which murmur intensity increases with standing?

Which murmur intensity increases with standing?

• A. Aortic stenosis
• B. Mitral regurgitation
• C. Tricuspid stenosis
• D. Atrial septal defect

Answer: (A)

When standing, venous return to the heart drops, so LV preload falls. Most murmurs that depend on the amount of flow through a valve soften with this reduced preload. The exception is a dynamic LV outflow tract obstruction, such as hypertrophic obstructive cardiomyopathy, where less preload makes the obstruction worse and the murmur louder. Looking at the options, the murmur of aortic stenosis typically decreases with standing because there is less flow across the narrowed valve. Mitral regurgitation generally softens as preload falls since there is less regurgitant volume, and tricuspid stenosis and the murmur from an atrial septal defect are not typically amplified by standing. The classic pattern you’d expect for increasing intensity with standing would be a dynamic obstruction like HOCM, which isn’t among these choices, suggesting a miskey if this question marks a different option as correct.

When standing, venous return to the heart drops, so LV preload falls. Most murmurs that depend on the amount of flow through a valve soften with this reduced preload. The exception is a dynamic LV outflow tract obstruction, such as hypertrophic obstructive cardiomyopathy, where less preload makes the obstruction worse and the murmur louder. Looking at the options, the murmur of aortic stenosis typically decreases with standing because there is less flow across the narrowed valve. Mitral regurgitation generally softens as preload falls since there is less regurgitant volume, and tricuspid stenosis and the murmur from an atrial septal defect are not typically amplified by standing. The classic pattern you’d expect for increasing intensity with standing would be a dynamic obstruction like HOCM, which isn’t among these choices, suggesting a miskey if this question marks a different option as correct.