What happens to the murmur of aortic stenosis (AS) with Valsalva maneuver?

The murmur of aortic stenosis typically decreases in intensity during the Valsalva maneuver. This maneuver increases intrathoracic pressure, which leads to a reduction in venous return to the heart. Since the severity of the murmur correlates with the degree of blood flow across the narrowed aortic valve, decreasing blood flow results in a softer murmur.

In cases of aortic stenosis, the typical systolic ejection murmur occurs during ventricular contraction as blood is ejected through the stenotic valve. When venous return is diminished due to the Valsalva maneuver, the stroke volume is reduced. This is reflected in the decreased intensity of the murmur, as there is less turbulence created by the blood flow through the narrowed valve.

Other responses do not accurately reflect the physiological changes occurring during the Valsalva maneuver in relation to aortic stenosis. Thus, understanding the impact of this maneuver on venous return and subsequently on cardiac output is crucial in recognizing how it affects the murmur associated with aortic stenosis.