Which maneuver is used to enhance the murmurs of hypertrophic obstructive cardiomyopathy?

The Valsalva maneuver is used to enhance the murmurs of hypertrophic obstructive cardiomyopathy (HOCM) due to its effects on the heart's hemodynamics. When a patient performs the Valsalva maneuver, they temporarily increase intrathoracic pressure by forcefully exhaling against a closed airway. This action leads to decreased venous return to the heart, reduced left ventricular volume, and subsequently less filling of the ventricles.

In the context of HOCM, which is characterized by asymmetric septal hypertrophy that can obstruct blood flow out of the left ventricle, a decrease in left ventricular volume can exacerbate the outflow tract obstruction. As a result, the intensity of the murmur associated with HOCM increases during the Valsalva maneuver. This occurs because the septal hypertrophy increases the likelihood of dynamic obstruction, enhancing the characteristic systolic ejection murmur.

Other maneuvers, such as squatting or hand grip, tend to increase venous return or systemic vascular resistance, thereby reducing the intensity of the murmur in HOCM. Standing up can similarly decrease venous return but may not have the same pronounced effect on enhancing the murmur as observed with Vals