Squatting (affect on different heart murmurs)

Squatting down causes an increase in venous return and systemic arterial hypertension. This results in an increased stroke volume and arterial pressure. The affect of these two factors is, in general, to make a heart murmur louder. However, this is not the case for:

• hypertrophic obstructive cardiomyopathy - where there is a reduction in intensity of the murmur because of an increased left ventricular size and therefore reduction in outflow obstruction.
• mitral valve prolapse - there is a delay in the midsystolic click and murmur.