From the Guidelines
The intensity of a ventricular septal defect (VSD) murmur generally correlates inversely with the size of the defect, with small VSDs producing loud murmurs and large VSDs often producing soft or no murmurs. This is because the pressure gradient between the ventricles creates significant turbulent blood flow through a restricted opening in small VSDs, resulting in a loud murmur 1. In contrast, large VSDs have a low resistance to flow, resulting in less turbulence and a quieter murmur.
Key Points to Consider
- Small VSDs typically produce loud, harsh holosystolic murmurs due to the significant turbulent blood flow through a restricted opening 1.
- Medium-sized VSDs may produce moderate murmurs, although the exact correlation between murmur intensity and defect size can be variable.
- Very large VSDs often produce soft murmurs or no murmur at all because the large opening allows blood to flow freely between ventricles with minimal turbulence 1.
- The left-to-right shunt may decrease over time in patients with large VSDs as pulmonary vascular resistance increases, further reducing murmur intensity.
Importance of Echocardiography
Echocardiography is essential for accurate assessment of defect size, shunt volume, and hemodynamic consequences, as murmur intensity alone is not a reliable indicator of VSD size or severity 1. Clinicians should not rely solely on murmur intensity to determine VSD size or severity, but rather use a combination of physical examination and echocardiography to guide diagnosis and management.
Management of VSD
The management of VSD depends on the size of the defect, the presence of symptoms, and the presence of complications such as pulmonary hypertension or aortic regurgitation 1. Small restrictive defects may be managed conservatively, while larger defects may require surgical or transcatheter closure. The decision to close a VSD should be made on a case-by-case basis, taking into account the individual patient's anatomy, physiology, and clinical status.
From the Research
VSD Murmur Intensity and Size Correlation
- The correlation between VSD murmur intensity and size is not directly addressed in the provided studies 2, 3, 4, 5, 6.
- However, the studies suggest that the size of the VSD is an important factor in determining the clinical significance and management of the defect 2, 4.
- A study published in 1992 found that Doppler echocardiography can be used to measure the peak interventricular pressure gradient across the VSD, which is a useful parameter for assessing pulmonary artery systolic pressure in patients with a VSD 6.
- The study also found that the peak shunt velocity and peak pressure gradient across the VSD on Doppler ultrasound imaging correlated well with measurements obtained by cardiac catheterization 6.
- Another study published in 2014 reported a case of a traumatic VSD that resulted in severe pulmonary hypertension, highlighting the importance of timely intervention for large VSDs to prevent pulmonary vascular obstructive disease 3.
- A review published in 2024 discussed the diagnosis and management of VSDs, including the classification of VSDs based on their size, number, and location in the ventricular septum 2.
- The review also noted that echo-Doppler studies are essential for assessing the defect's clinical significance and determining the need for intervention 2.
Factors Influencing VSD Murmur Intensity
- The intensity of the VSD murmur may be influenced by several factors, including the size of the defect, the presence of pulmonary hypertension, and the location of the defect in the ventricular septum 4, 5.
- A study published in 2015 found that targeted drug therapy can be used to decrease pulmonary circulation resistance in patients with non-restrictive VSD and severe pulmonary hypertension, which may affect the intensity of the murmur 5.
- The study also found that the "treat and repair" strategy may be a viable approach for adults with non-restrictive VSD and severe pulmonary hypertension 5.