From the Guidelines
Murmurs that increase with the Valsalva maneuver include hypertrophic cardiomyopathy (HCM) and mitral valve prolapse (MVP). The Valsalva maneuver involves forceful exhalation against a closed airway, which decreases venous return to the heart and reduces left ventricular volume. In HCM, this maneuver exacerbates the obstruction in the left ventricular outflow tract, making the systolic murmur louder, as noted in the guidelines by the American College of Cardiology/American Heart Association 1. For mitral valve prolapse, the reduced ventricular filling causes the mitral valve to prolapse more prominently into the left atrium, intensifying the mid-to-late systolic click and murmur.
Some key points to consider when evaluating murmurs with the Valsalva maneuver include:
- The effect of the Valsalva maneuver on different types of murmurs, with most murmurs decreasing in length and intensity, except for HCM and MVP, which increase 1.
- The importance of distinguishing between different cardiac conditions based on their response to the Valsalva maneuver, as this can inform diagnosis and treatment decisions.
- The role of other factors, such as respiration, exercise, and positional changes, in altering the intensity of cardiac murmurs, as outlined in the guidelines 1.
In clinical practice, the Valsalva maneuver can be a useful diagnostic tool for distinguishing between different cardiac conditions, particularly when used in conjunction with other physical examination findings and diagnostic tests. By understanding how different murmurs respond to the Valsalva maneuver, clinicians can refine their diagnosis and develop effective treatment plans, ultimately improving patient outcomes in terms of morbidity, mortality, and quality of life.
From the Research
Murmurs that Increase with Valsalva
The Valsalva maneuver is a technique used to evaluate heart murmurs. The following murmurs are known to increase with the Valsalva maneuver:
- Murmur of hypertrophic cardiomyopathy: This murmur is distinguished from other murmurs by an increase in intensity with the Valsalva maneuver 2
- Left ventricular outflow tract obstruction in hypertrophic cardiomyopathy: The Valsalva maneuver is used to provoke left ventricular outflow tract obstruction in hypertrophic cardiomyopathy, and the murmur intensity increases with the maneuver 3, 4
Mechanism of Increase
The increase in murmur intensity with the Valsalva maneuver is due to the decrease in venous return and subsequent decrease in left ventricular preload, which leads to an increase in the dynamic obstruction of the left ventricular outflow tract 5
Clinical Implications
The Valsalva maneuver is a useful tool in the clinical evaluation of patients with hypertrophic cardiomyopathy, as it can help to diagnose and assess the severity of left ventricular outflow tract obstruction 3, 4