The four pulmonary veins (right superior, right inferior, left superior, left inferior) carry oxygenated blood from the lung parenchyma to the left atrium. They are the only veins in the body that carry arterial blood. The right pulmonary veins pass posterior to the right atrium and the superior vena cava. The left pulmonary veins pass anterior to the descending thoracic aorta. They drain into the left atrium without valves, and may vary with a common left trunk or accessory right middle lobe vein.
The pulmonary vein ostia are the source of ectopic electrical foci that trigger atrial fibrillation in the majority of paroxysmal AF patients. Radiofrequency or cryoablation catheter techniques electrically isolate each pulmonary vein from the left atrium (pulmonary vein isolation, PVI), the cornerstone of interventional AF treatment. Pulmonary vein stenosis is a recognised complication of ablation if the ostial tissue is injured. In lung resection surgery, the inferior and superior pulmonary veins are individually ligated and divided before the bronchus.
Catheter ablation creating electrical isolation around all four pulmonary vein ostia eliminates the ectopic triggers of paroxysmal atrial fibrillation in 60-80% of patients at one year, with repeat procedures improving long-term success rates.
Excessive energy delivery at the pulmonary vein ostium during AF ablation causes fibrotic narrowing producing exertional dyspnoea, haemoptysis, and reduced perfusion of the corresponding lobe, diagnosed by CT angiography and treated by percutaneous balloon angioplasty or stenting.
