From the Guidelines
Atrial Septal Defect (ASD) is typically associated with fixed splitting of the second heart sound (S2), which is a key diagnostic finding 1.
Key Heart Sounds
- Fixed splitting of S2: This occurs during both inspiration and expiration, and is a characteristic feature of ASD 1.
- Systolic pulmonary flow murmur: This murmur is often heard in patients with ASD, particularly those with a significant left-to-right shunt 1.
Diagnostic Considerations
The presence of fixed splitting of S2, along with other clinical findings such as a systolic pulmonary flow murmur, should raise suspicion for ASD 1.
Evidence Summary
The evidence from multiple studies, including those published in the European Heart Journal 1 and Circulation 1, consistently supports the association between ASD and fixed splitting of S2.
Clinical Implications
In clinical practice, the presence of fixed splitting of S2 should prompt further evaluation for ASD, particularly in patients with other suggestive clinical findings or risk factors 1.
From the Research
Heart Sounds Associated with Atrial Septal Defect (ASD)
- The first heart sound in ASD is characterized by an attenuated mitral component and an accentuated tricuspid component 2
- The interval between the first heart sound and the beginning of systolic murmur or the respiratory variation of the second heart sound (S2) can be used to distinguish ASD from physiological murmur 3
- The second heart sound (S2) is often fixed and split in patients with ASD 4
- The spectrum of systolic murmur and the frequency of the murmur at its maximum intensity can also be used to diagnose ASD 3
- Hemodynamic alterations and consequent changes in closing energies of the atrioventricular valves probably account for the characteristics of the first heart sound in ASD 2
- A midsystolic pulmonary flow or ejection murmur, accompanied by a fixed split-second heart sound, is a characteristic physical finding in patients with ASD 4