How do Valsalva maneuver, standing, squatting, and Trendelenburg position affect heart murmurs?

From the Guidelines

The Valsalva maneuver and standing typically decrease the intensity of most heart murmurs, while squatting and the Trendelenburg position increase their intensity, except for murmurs associated with hypertrophic cardiomyopathy (HCM) and mitral valve prolapse (MVP), which behave oppositely. The effects of these maneuvers on heart murmurs can be understood by considering their impact on cardiac preload and afterload.

• The Valsalva maneuver decreases venous return to the heart, reducing the intensity of most murmurs, as noted in the acc/aha 2006 guidelines 1.
• Standing similarly decreases venous return, making most murmurs softer, while accentuating HCM murmurs, as they become louder with decreased venous return 1.
• Squatting increases venous return and peripheral resistance, intensifying most murmurs but decreasing HCM murmurs, which become softer due to increased venous return 1.
• The Trendelenburg position increases venous return to the heart, making most murmurs louder, except for HCM murmurs, which become softer due to the increased preload 1. These maneuvers are essential in differentiating between murmur types during cardiac examination, allowing clinicians to make more accurate diagnoses without requiring advanced imaging in the initial evaluation. For instance, a murmur that gets louder with standing and Valsalva but softer with squatting strongly suggests HCM, as noted in the guidelines 1. Understanding the relationships between these physiological maneuvers and murmur intensity enables clinicians to apply this knowledge in real-life clinical practice, ultimately improving patient outcomes in terms of morbidity, mortality, and quality of life.

From the Research

Effects of Valsalva Maneuver, Standing, Squatting, and Trendelenburg Position on Heart Murmurs

• The Valsalva maneuver increases intrathoracic pressure, which decreases venous return to the heart and increases peripheral venous pressures 2.
• Standing up can decrease venous return to the heart, which can affect heart murmurs, whereas squatting can increase venous return, potentially altering the characteristics of heart murmurs 3.
• The Trendelenburg position, which involves tilting the patient in a supine position so that their head is lower than their pelvis, can increase venous return to the heart, similar to squatting 4.
• The effects of these maneuvers on heart murmurs depend on the underlying cardiac condition, with different maneuvers affecting preload, afterload, chamber dimensions, and pressure gradients in various ways 3.

Comparison of Maneuvers

• The Valsalva maneuver and standing up tend to decrease preload, which can reduce the intensity of certain heart murmurs, such as those associated with mitral regurgitation 2, 3.
• Squatting and the Trendelenburg position tend to increase preload, which can increase the intensity of certain heart murmurs, such as those associated with aortic stenosis 4, 3.
• The specific effects of these maneuvers on heart murmurs can vary depending on the individual patient and the underlying cardiac condition, highlighting the importance of a thorough physical examination and diagnostic evaluation 5, 6.

Clinical Implications

• Understanding the effects of different maneuvers on heart murmurs can aid in the diagnosis and management of cardiac conditions, such as aortic stenosis and mitral regurgitation 5, 6.
• The use of maneuvers like the Valsalva maneuver, standing, squatting, and Trendelenburg position can provide valuable information about the hemodynamic effects of different cardiac conditions and guide treatment decisions 3.