Which finding on imaging best indicates pulmonary vein stenosis after atrial fibrillation ablation?

• A. Dyspnea or chest symptoms.
• B. Normal CT angiography.
• C. Decreased PV cross-sectional area on CT/MRI angiography or Doppler.
• D. Increased PV cross-sectional area on imaging.

Answer: (C)

Pulmonary vein stenosis after atrial fibrillation ablation is diagnosed most directly by seeing narrowing of the vein lumen at the ostium on imaging. On CT or MR angiography, this shows up as a decreased cross-sectional area of the affected pulmonary veins. Doppler adds functional context by often showing higher flow velocity across the narrowed segment or altered flow, confirming hemodynamic impact. Symptoms like dyspnea or chest pain can occur but are nonspecific, so the imaging finding of a reduced vein area is the clearest indicator. A normal CT angiography argues against stenosis, and an increased (dilated) cross-sectional area would not indicate stenosis.