From the Guidelines
A harsh holosystolic murmur at the lower left and right sternal borders is most commonly caused by ventricular septal defect (VSD). This abnormal opening in the wall between the left and right ventricles allows blood to flow from the higher-pressure left ventricle to the lower-pressure right ventricle throughout systole, creating the characteristic harsh murmur 1. The location of the murmur corresponds to the anatomical position of the defect, with lower sternal border murmurs typically indicating membranous or muscular VSDs.
Key Characteristics of the Murmur
- The intensity of the murmur relates to the size of the defect and the pressure gradient between ventricles.
- Smaller defects often produce louder murmurs due to higher-velocity flow through the restricted opening.
- Other less common causes of similar murmurs include tricuspid regurgitation, which may be distinguished by its increase during inspiration, and mitral regurgitation with unusual radiation patterns 1.
Diagnostic Approach
Physical examination findings that support a VSD diagnosis include a palpable thrill at the left sternal border and potentially signs of heart failure in large defects. Echocardiography is the definitive diagnostic tool to confirm the presence, size, and hemodynamic significance of a VSD 1. It is essential for defining the primary lesion, hemodynamics, coexisting abnormalities, and secondary lesions, as well as evaluating cardiac chamber size and function.
Clinical Considerations
In evaluating heart murmurs, it's crucial to consider the timing, location, and radiation of the murmur, as well as the patient's symptoms and other physical findings. The approach to the patient may vary greatly depending on these considerations, and echocardiography is recommended for patients with certain types of murmurs or symptoms suggestive of significant heart disease 1.
From the Research
Causes of Harsh Holosystolic Murmur
- A harsh holosystolic murmur at the lower left and right sternal borders can be caused by tricuspid regurgitation (TR) 2, which is a condition where the tricuspid valve does not close properly, allowing blood to flow backward into the right atrium.
- TR can be functional, caused by cardiomyopathies, left ventricular valve disease, or pulmonary disease, or it can be due to structural abnormalities of the tricuspid valve, such as those encountered in complete transposition of the great arteries with ventricular septal defect 3.
- Traumatic tricuspid insufficiency, which can occur due to chest blunt trauma, can also cause a holosystolic murmur at the lower left and right sternal borders 4.
- In children, a holosystolic murmur can be a sign of underlying heart disease, and referral to a pediatric cardiologist is recommended for evaluation and management 5.
- Significant tricuspid regurgitation is common in heart failure and portends poor prognosis, but it may not be an independent risk factor for readmission or mortality in the absence of pulmonary hypertension 6.
Associated Conditions
- Tricuspid regurgitation is often associated with other cardiac abnormalities, such as reduced left ventricular systolic function, moderate or severe mitral regurgitation, pulmonary hypertension, and right ventricular dysfunction 6.
- The presence of pulmonary hypertension can increase the risk of readmission or mortality in patients with significant tricuspid regurgitation 6.