Which maneuver would typically decrease the murmur intensity of hypertrophic cardiomyopathy?

Which maneuver would typically decrease the murmur intensity of hypertrophic cardiomyopathy?

• A. Valsalva maneuver
• B. Standing from squatting
• C. Tachycardia
• D. Squatting

Answer: (D)

Hypertrophic cardiomyopathy murmur strength depends on how dynamic LV outflow tract obstruction changes with preload and contractility. Increasing preload and LV volume tends to lessen the obstruction, softening the murmur, while decreasing preload or increasing contractility tends to worsen the obstruction and make the murmur louder. Squatting raises venous return and left ventricular filling, increasing preload and LV size, which reduces the obstruction across the outflow tract and results in a softer murmur. Conversely, maneuvers that reduce preload, like Valsalva or standing from a squat, or states that raise heart rate and contractility, tend to heighten the obstruction and intensify the murmur. So squatting is the maneuver that typically decreases murmur intensity.

Hypertrophic cardiomyopathy murmur strength depends on how dynamic LV outflow tract obstruction changes with preload and contractility. Increasing preload and LV volume tends to lessen the obstruction, softening the murmur, while decreasing preload or increasing contractility tends to worsen the obstruction and make the murmur louder. Squatting raises venous return and left ventricular filling, increasing preload and LV size, which reduces the obstruction across the outflow tract and results in a softer murmur. Conversely, maneuvers that reduce preload, like Valsalva or standing from a squat, or states that raise heart rate and contractility, tend to heighten the obstruction and intensify the murmur. So squatting is the maneuver that typically decreases murmur intensity.