Atrial Septal Defect vs Ventricular Septal Defect
Atrial Septal Defect and Ventricular Septal Defect are easy to mix up on the boards. Here's a side-by-side comparison — presentation, workup, imaging, and first-line treatment — drawn from our full outlines.
Atrial Septal Defect vs Ventricular Septal Defect at a glance
- Atrial Septal Defect: Opening in the interatrial septum producing left-to-right shunt, fixed split S2, and risk of paradoxical embolism.
- Ventricular Septal Defect: Opening in the interventricular septum causing a left-to-right shunt with a harsh holosystolic murmur at the LLSB.
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Side-by-side comparison
| Feature | Atrial Septal Defect | Ventricular Septal Defect |
|---|---|---|
| At a glance | Opening in the interatrial septum producing left-to-right shunt, fixed split S2, and risk of paradoxical embolism. | Opening in the interventricular septum causing a left-to-right shunt with a harsh holosystolic murmur at the LLSB. |
| Classic presentation | Wide and fixed split S2 with pulmonic flow murmur in an otherwise asymptomatic adult.; Often asymptomatic in childhood; diagnosed in adulthood after decades of right heart volume overload; Exertional dyspnea, fatigue, palpitations (atrial arrhythmias); Recurrent respiratory infections in larger defects; Cryptogenic stroke or TIA… | Harsh, blowing holosystolic murmur with palpable thrill at the LLSB; intensity inversely related to defect size in many cases.; Small VSD: asymptomatic, identified by murmur on routine examination; Moderate-to-large VSD in infancy: poor feeding, diaphoresis with feeds, failure to thrive, tachypnea, recurrent pulmonary infections, signs… |
| Workup / key labs | Hemodynamically significant ASD warranting closure: right heart enlargement on imaging and Qp/Qs ≥1.5, OR documented paradoxical embolism, OR platypnea-orthodeoxia. Closure is generally contraindicated if pulmonary vascular resistance is severely elevated and irreversible.; Basic labs typically unremarkable; BNP may be elevated if… | Basic labs are typically normal; BNP if HF symptoms |
| Imaging | Transthoracic echocardiography with agitated saline (bubble study) and color Doppler — visualizes defect, direction and magnitude of shunt, RA/RV size, RV function, and estimates pulmonary pressures; Transesophageal echocardiography for better characterization of sinus venosus and sinus coronarius defects and to evaluate suitability for… | Transthoracic echocardiography with color Doppler — diagnostic; defines anatomy, size, shunt direction, chamber size, RV pressure, presence of AR (especially outlet VSD) or AV valve abnormalities; ECG: normal in small VSDs; LA enlargement and LVH with moderate-to-large shunts; biventricular hypertrophy with significant pulmonary HTN;… |
| First-line treatment | Secundum ASD: percutaneous transcatheter device closure (e.g., Amplatzer septal occluder) is the preferred approach when anatomy is suitable (adequate rims, defect <38 mm); Primum, sinus venosus, and unroofed coronary sinus defects, as well as secundum defects with inadequate rims: surgical patch closure; Dual antiplatelet therapy… | Small, restrictive, asymptomatic VSD: observation; spontaneous closure is common in muscular and small perimembranous defects; Hemodynamically significant VSD (HF symptoms, growth failure, pulmonary hypertension reversible): surgical patch closure is the standard, typically in infancy or early childhood; Selected muscular VSDs may be… |
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