Hypertrophic Cardiomyopathy Murmur Characteristics

Characteristic Dynamic Responses

• The American College of Cardiology notes that the systolic murmur of hypertrophic cardiomyopathy (HCM) decreases in intensity when moving from standing to squatting and increases with the Valsalva maneuver 1, 2, 3
• The Valsalva maneuver increases the intensity of the HCM murmur, while most other murmurs decrease in length and intensity, as reported by the American College of Cardiology 1, 2, 3, 4
• Standing from a squatting position increases the intensity of the HCM murmur, unlike most other murmurs which diminish, according to the American College of Cardiology 1, 2, 3
• Squatting from a standing position decreases the intensity of the HCM murmur, with a reported sensitivity of 95% and specificity of 85% for HCM diagnosis, as noted by the American College of Cardiology 1, 2, 3

Clinical Distinction from Other Murmurs

• The American College of Cardiology states that the HCM murmur becomes louder with standing, unlike most other murmurs which diminish 1, 2, 3
• Mitral valve prolapse (MVP) murmurs also lengthen and intensify with standing, but can be distinguished from HCM because MVP murmurs do not have the same dramatic response to squatting, as reported by the American College of Cardiology 1, 2, 3