PR-segment depression during cryoballoon ablation of atrial fibrillation: a case report

Cryoballoon ablation has been widely used in the treatment of atrial fibrillation (AF). The main complications of the procedure include pericardial tamponade, pulmonary vein stenosis, and atrial esophageal leakage, etc. But there has been hardly any reporting of PR-segment changes caused by cryoballoon ablation of AF. In this case report, we describe the patient with a sudden onset of chest pain during the treatment of AF using cryoballoon ablation, and electrocardiogram (ECG) showed depressed PR-segment in the lead on the inferior wall lead, which was a manifestation of atrial ischemia.  The patient was a 50-year-old man who was admitted to General Hospital of Northern Theater Command, Shenyang, China for catheter ablation treatment of AF. The patient had a history of hypertension, diabetes and cerebral infarction, the CHA2DS2-VASc score of 4 points, and was on a medication of dabigatran 150 mg. On admission, his ECG was normal with a sinus rhythm. During a seizure, the ECG documented AF. Echocardiography showed the left atrium dimension as 31 mm, the left ventricle dimension as 46 mm, and the left ventricular ejection fraction as 63%. Transthoracic echocardiography did not reveal any atrial thrombus. In addition, pulmonary venous computed tomography angiography showed no obvious abnormalities of the pulmonary veins. The patient signed the informed consent form for the procedure, and then began the frozen balloon ablation of AF. His preoperative ECG was shown in Figure 1A. Conventional puncturing of the femoral vein and internal jugular vein aimed to lay the right ventricular electrode and coronary sinus electrode, and puncturing of the atrial septum