American Board of Internal Medicine (ABIM) Certification Practice Exam

What complication may arise after catheter ablation of atrial fibrillation and present with unexplained dyspnea?

1. Pulmonary vein stenosis

2. Heart valve regurgitation

3. Myocardial infarction

4. Atrial flutter

The correct answer is: Pulmonary vein stenosis

Pulmonary vein stenosis is a recognized complication that may occur following catheter ablation for atrial fibrillation. During the ablation procedure, the pulmonary veins, which are targeted for isolation to prevent the reentry of abnormal electrical signals, can be inadvertently injured. This injury can lead to scarring and narrowing of the veins, resulting in pulmonary vein stenosis. Unexplained dyspnea in a patient who has undergone catheter ablation may be due to this stenosis as it can cause increased pressure in the pulmonary circulation, leading to pulmonary congestion and resulting difficulty in breathing. The symptoms arise as the flow of blood is hindered with reduced capacity to transport oxygen efficiently, which manifests as shortness of breath. In contrast, the other complications listed—heart valve regurgitation, myocardial infarction, and atrial flutter—while they may occur in patients with atrial fibrillation or following catheter procedures, are not specifically associated with the mechanism of pulmonary vein isolation or the resultant hemodynamic changes leading to unexplained dyspnea. Thus, pulmonary vein stenosis is the most pertinent explanation for this scenario.