Differential Diagnosis for Murmur Improved with Squat
- Single most likely diagnosis
- Hypertrophic Obstructive Cardiomyopathy (HOCM): This condition is characterized by an asymmetrically hypertrophied left ventricle, which can cause a dynamic left ventricular outflow tract obstruction. The murmur of HOCM typically decreases with squatting due to increased venous return, which increases left ventricular volume and reduces the obstruction.
- Other Likely diagnoses
- Mitral Valve Prolapse: Although the murmur of mitral valve prolapse typically worsens with maneuvers that decrease left ventricular volume (such as standing or Valsalva), some patients may exhibit a decrease in murmur intensity with squatting due to increased left ventricular volume.
- Aortic Stenosis: The murmur of aortic stenosis may not always follow the typical pattern, and in some cases, it may decrease with squatting, although this is less common.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Cardiac Tamponade: Although the murmur may not be directly related to the improvement with squatting, cardiac tamponade can cause a decrease in cardiac output, which may be partially alleviated by increased venous return with squatting. It's crucial to consider this diagnosis due to its high mortality rate if left untreated.
- Pulmonary Embolism: While not directly related to the murmur, pulmonary embolism can cause a decrease in cardiac output, and squatting may increase venous return, temporarily improving symptoms.
- Rare diagnoses
- Congenital Heart Defects (e.g., atrial septal defect, ventricular septal defect): Some congenital heart defects may exhibit murmurs that change with position or maneuvers, although this is less common.
- Cardiac Tumors (e.g., left atrial myxoma): Cardiac tumors can cause obstructive symptoms and murmurs, which may change with position or maneuvers, including squatting.