Patent Ductus Arteriosus vs Atrial Septal Defect
Patent Ductus Arteriosus and Atrial 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.
Patent Ductus Arteriosus vs Atrial Septal Defect at a glance
- Patent Ductus Arteriosus: Persistent fetal connection between aorta and pulmonary artery producing a continuous machinery murmur and L-to-R shunt.
- Atrial Septal Defect: Opening in the interatrial septum producing left-to-right shunt, fixed split S2, and risk of paradoxical embolism.
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Side-by-side comparison
| Feature | Patent Ductus Arteriosus | Atrial Septal Defect |
|---|---|---|
| At a glance | Persistent fetal connection between aorta and pulmonary artery producing a continuous machinery murmur and L-to-R shunt. | Opening in the interatrial septum producing left-to-right shunt, fixed split S2, and risk of paradoxical embolism. |
| Classic presentation | Continuous machinery murmur with wide pulse pressure and bounding pulses in a child; differential cyanosis is pathognomonic when shunt reversal develops.; Small PDA: asymptomatic, found incidentally on auscultation; Moderate-to-large PDA in infancy: poor feeding, diaphoresis with feeds, failure to thrive, tachypnea, recurrent pulmonary… | 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… |
| Workup / key labs | BMP, CBC; Genetic evaluation if features suggest a syndrome (Down, rubella exposure history) | 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… |
| Imaging | Transthoracic echocardiography with color Doppler — diagnostic; visualizes the ductus, direction and velocity of shunt, and chamber size; ECG: normal if small; LA enlargement and LVH with large shunts; biventricular hypertrophy with pulmonary HTN; CXR: cardiomegaly, prominent pulmonary vasculature, dilated proximal pulmonary arteries in… | 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… |
| First-line treatment | Premature infants (hemodynamically significant PDA): supportive care first (fluid restriction, diuretics, optimize ventilation). Pharmacologic closure with indomethacin or ibuprofen (COX inhibitors) — first-line; acetaminophen is an alternative when COX inhibitors are contraindicated; Term infants and older children with persistent PDA:… | 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… |
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