How does squatting affect the murmur of aortic stenosis (AS)?

Squatting has a significant impact on the murmurs associated with various cardiac conditions, including aortic stenosis (AS). In the case of aortic stenosis, squatting increases systemic vascular resistance, leading to increased venous return to the heart. This results in enhanced left ventricular preload and, consequently, a greater stroke volume.

In the presence of aortic stenosis, the increased blood flow through the narrowed aortic valve causes the characteristic systolic ejection murmur to become louder. This is due to the higher velocity of blood flow across the stenotic valve as systemic resistance increases during the squatting maneuver.

Additionally, the left ventricular outflow tract (which contains the aortic valve) experiences heightened pressure due to the increased volume of blood being ejected with each heartbeat. The combination of these factors results in a louder murmur, which can be assessed by auscultation.

Overall, squatting accentuates the murmur associated with aortic stenosis due to the physiological changes in blood flow dynamics, making it the correct response in this context.