Systolic Murmur Differential Diagnosis
The differential diagnosis for a systolic murmur can be organized into the following categories:
- Single Most Likely Diagnosis
- Aortic stenosis: This is often considered the most likely diagnosis for a systolic murmur, particularly in older adults, due to the high prevalence of aortic valve disease. The murmur of aortic stenosis is typically a harsh, crescendo-decrescendo systolic murmur best heard at the right second intercostal space.
- Other Likely Diagnoses
- Mitral regurgitation: This condition is characterized by a holosystolic or late systolic murmur best heard at the apex. It is a common cause of systolic murmurs, especially in patients with heart failure or coronary artery disease.
- Tricuspid regurgitation: This condition presents with a holosystolic murmur best heard at the left lower sternal border, which may increase with inspiration. It is often associated with signs of right heart failure.
- Pulmonic stenosis: Although less common, pulmonic stenosis can cause a systolic murmur, typically heard at the left second intercostal space, and is often associated with a widely split S2.
- Do Not Miss Diagnoses
- Hypertrophic cardiomyopathy: This condition can cause a dynamic systolic murmur due to left ventricular outflow tract obstruction, which may be exacerbated by maneuvers that decrease ventricular preload. Missing this diagnosis can be fatal due to the risk of sudden cardiac death.
- Aortic dissection: Although not typically the first diagnosis considered for a systolic murmur, a new or changing murmur in the context of severe chest pain could indicate an aortic dissection, which is a medical emergency.
- Rare Diagnoses
- Congenital heart defects (e.g., ventricular septal defects, atrial septal defects): These can present with systolic murmurs and are more common in pediatric populations but can also be diagnosed in adults.
- Cardiac tumors (e.g., atrial myxoma): These are rare causes of systolic murmurs but can be considered in the differential diagnosis, especially if there are other systemic symptoms or signs suggestive of a tumor.
- Infective endocarditis: While not rare, it is a serious condition that can cause new or changing heart murmurs, including systolic murmurs, and requires prompt diagnosis and treatment to prevent complications.