What is partial anomalous pulmonary venous return (PAPVR)?

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Last updated: September 30, 2026 • View editorial policy

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What is PAPVR?

Partial anomalous pulmonary venous return (PAPVR) is a congenital heart defect in which one or more pulmonary veins drain abnormally into the right atrium or systemic venous circulation (such as the superior or inferior vena cava) instead of the left atrium, creating a left-to-right shunt that causes right heart volume overload 1.

Pathophysiology

PAPVR creates an abnormal connection between a pulmonary vein and the systemic venous system, resulting in:

  • Volume overload of the right heart with physiological effects similar to an atrial septal defect (ASD)
  • Left-to-right shunting of oxygenated blood back to the right side of the heart
  • Unlike ASD, there is no potential for right-to-left shunting in isolated PAPVR
  • The shunt magnitude is not worsened by acquired left heart disease 1

Common Anatomic Variants

The most frequent patterns include 1:

  • Right upper pulmonary vein to superior vena cava (most common) - often associated with sinus venosus defect
  • Right pulmonary vein(s) to inferior vena cava via a "scimitar vein" - associated with higher risk of Eisenmenger syndrome
  • Left-sided anomalous connections (less common) - may drain to left innominate vein 2

Clinical Presentation

PAPVR is increasingly diagnosed in adults due to widespread use of cross-sectional imaging 3:

  • Incidental finding on chest CT (prevalence approximately 0.2%) 4
  • Symptomatic presentations: exertional dyspnea, atrial arrhythmias, lower extremity edema 5
  • Right ventricular enlargement and volume overload 4, 5
  • Pulmonary arterial hypertension develops in approximately 14% of adult cases 4

Important Caveat

Over half (54%) of incidentally diagnosed PAPVR patients do not receive appropriate cardiac follow-up 4, which can lead to progressive right heart remodeling and pulmonary vascular disease. When unexplained right atrial enlargement is present, PAPVR should be strongly suspected 5.

Hemodynamic Consequences

The physiological impact depends on shunt magnitude 1:

  • Volume overload effects: Increased RV volumes, RV basal diameter typically 45±8 mm, RV/LV ratio 1.2±0.2 4
  • Pressure overload effects (when PAH develops): Decreased RV functional parameters (fractional area change 35±13%, global longitudinal strain -18±5%) 4
  • Qp:Qs ratio is the only predictor of pulmonary arterial hypertension development 4

Key Diagnostic Principle

A single anomalous pulmonary vein from one lobe rarely causes sufficient volume load to produce symptoms, but multiple anomalous veins with moderate-to-large shunts (Qp:Qs ≥1.5:1) lead to clinically significant RV enlargement and warrant intervention 1.

References

2
Research

Delayed Diagnosis of Partial Anomalous Pulmonary Venous Return in an Adult With Pulmonary Hypertension.

Journal of investigative medicine high impact case reports, 2025

4
Research

Partial anomalous pulmonary venous return in adults: Insight into pulmonary hypertension.

International journal of cardiology. Congenital heart disease, 2023

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This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.