During handgrip, what physiologic change occurs that affects murmur intensity?

During a handgrip maneuver, there is an increase in systemic vascular resistance, which leads to an increase in afterload. This physiological change has a significant impact on the intensity of heart murmurs, particularly those associated with aortic regurgitation and mitral regurgitation.

When the afterload is increased, the heart has to work harder to pump blood against the higher pressure in the aorta or systemic circulation. In cases of aortic regurgitation, for example, the left ventricle's volume overload becomes more pronounced, and the murmur associated with the regurgitation may become louder as a result. Similarly, in mitral regurgitation, the increased afterload may increase the severity of the backflow and thus enhance the murmur's intensity.

Ultimately, understanding how handgrip affects hemodynamics—specifically, how it increases afterload—helps in recognizing and interpreting changes in murmur intensity during a physical examination. This principle is essential in evaluating various cardiac conditions and understanding their underlying pathophysiology.