The Practice of Catheter Cryoablation for Cardiac Arrhythmias

Edited by Ngai-Yin Chan

The Practice of Catheter Cryoablation for Cardiac ArrhythmiasThe Practice of Catheter Cryoablation for Cardiac Arrhythmias

Cases

Case 6.1. Prevention of phrenic nerve palsy during cryoballoon ablation for atrial fibrillation

A 67-year-old man with a previous history of coronary artery disease with preserved left ventricular (LV) function, coronary artery bypass grafting (CABG) 5 years ago, and paroxysmal highly symptomatic atrial fibrillation who had failed previous antiarrhythmic therapy is referred for possible ablation. Patient complains of significant shortening of breath with exercise since CABG. He denies history of smoking or prior respiratory disease. However, after his surgery, the patient remained intubated for 2 weeks. Currently he denies chest pain, cough, fever, or syncope. His physical exam is unremarkable except for decreased breathing sounds on the left.

  • 1. What is the best next test prior to cryoballoon ablation – pulmonary function test, chest X-ray, stress test, computed tomography (CT) of the chest, or proceed directly to cryoballoon ablation?

    Correct answer:The best option is inspiration and exhalation chest X-ray.
    Given the patient's prolonged intubation after CABG, his shortness of breath, and the physical findings, this patient has left phrenic nerve palsy. Phrenic nerve palsy can be confirmed by finding left hemidiaphragm elevation on exhalation and inhalation chest X-ray. The left phrenic nerve palsy is an important finding prior to cryoballoon ablation as possible paralysis of the right phrenic nerve will cause bilateral diaphragmatic paralysis and respiratory failure. If the patent is suspected of phrenic nerve compromise, chest X-ray prior to procedure will confirm the diagnosis. (See also Audio Clip 6.1.)

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