Patent Ductus Arteriosus vs Ventricular Septal Defect
Patent Ductus Arteriosus 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.
Patent Ductus Arteriosus vs Ventricular 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.
- 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 | Patent Ductus Arteriosus | Ventricular 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 interventricular septum causing a left-to-right shunt with a harsh holosystolic murmur at the LLSB. |
| 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… | 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 | BMP, CBC; Genetic evaluation if features suggest a syndrome (Down, rubella exposure history) | Basic labs are typically normal; BNP if HF symptoms |
| 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 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 | 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:… | 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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