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Difficulty: HardCardiovascular System

During bedside cardiovascular examination, various physical maneuvers and pharmacologic interventions are utilized to differentiate structural heart diseases by altering hemodynamics. Match each of the following maneuvers with its characteristic effect on the intensity of specific cardiac murmurs.

  • Valsalva maneuver (strain phase)Increases the intensity of the murmur in hypertrophic cardiomyopathy and decreases the intensity of the murmur in aortic stenosis.
  • Rapid squatting from a standing positionDecreases the intensity of the murmur in hypertrophic cardiomyopathy and increases the intensity of the murmur in aortic stenosis.
  • Isometric handgripIncreases the intensity of the murmur in aortic regurgitation and decreases the intensity of the murmur in aortic stenosis.
  • Amyl nitrite inhalationIncreases the intensity of the murmur in both aortic stenosis and hypertrophic cardiomyopathy, while decreasing the murmur of mitral regurgitation.

Answer

Valsalva matches increased HCM/decreased AS; Squatting matches decreased HCM/increased AS; Handgrip matches increased AR/decreased AS; Amyl nitrite matches increased AS/increased HCM/decreased MR.
Each physical maneuver uniquely alters preload and afterload, predictably affecting the pressure gradients and volumes that determine murmur intensity.

Step-by-Step Solution

1
Analyze the hemodynamic effect of the Valsalva maneuver.
It decreases venous return (preload).
Decreased preload reduces LV volume, which worsens HCM obstruction (louder murmur) but decreases flow across the aortic valve (softer AS murmur).
2
Analyze the hemodynamic effect of rapid squatting.
It increases preload and afterload.
Increased LV volume relieves HCM obstruction (softer murmur) but increases forward flow (louder AS murmur).
3
Analyze the hemodynamic effect of isometric handgrip.
It primarily increases afterload.
Higher aortic pressure increases regurgitant flow in AR (louder murmur) but decreases the pressure gradient across the stenotic aortic valve (softer AS murmur).
4
Analyze the hemodynamic effect of amyl nitrite.
It decreases afterload via arterial vasodilation.
Lower aortic pressure increases forward flow (louder AS murmur) and worsens LV outflow obstruction (louder HCM murmur), while reducing backward flow (softer MR murmur).

Key Concept

Hemodynamic effects of bedside maneuvers on structural cardiac murmurs
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Topics

Cardiovascular System

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