Pulmonary-vein stenosis can mimic massive pulmonary embolism after radiofrequency ablation for atrial fibrillation.

Pulmonary embolism, a medical emergency for pulmonary physicians, is defined as a blockage of the main artery of the lung or one of its branches by embolism, from many sources, such as thrombus, air, amniotic fluid, tumor, or fat.1 A good clinician, especially a pulmonary or critical care physician, should consider the possible diagnosis of pulmonary embolism in a highly suspected patient, since prompt diagnosis and treatment can dramatically reduce the morbidity and mortality of this disease. Because of the nonspecific signs and symptoms of pulmonary embolism, imaging is the key to diagnosis. Computed tomography pulmonary angiography (CTPA) has high sensitivity and specificity for pulmonary embolism and is the accepted standard in pulmonary embolism diagnosis.2,3 Combined application of CTPA and ventilation-perfusion (V̇/Q̇) lung scan provides a definite diagnosis in 90–99% of suspected patients.1 However, some CTPA findings can lead to a false-positive diagnosis of pulmonary embolism.4 We report a patient who was misdiagnosed with pulmonary embolism after radiofrequency-catheter ablation for atrial fibrillation. Both CTPA and V̇/Q̇ scan indicated a filling defect in the left main pulmonary artery, which was interpreted as a massive pulmonary embolism, but pulmonary angiography revealed that the true diagnosis was pulmonary-vein stenosis. Case Summary