Abstract 12154: “Hands-Free” Non-Fluoroscopic Monitoring of Phrenic Nerve Function During Catheter Ablation
Diaphragm motion (DM) is usually assessed by fluoroscopy and manual palpation (F/MP) to avoid phrenic nerve (PN) damage during catheter ablation. We tested a new “hands-free” nonfluoroscopic method for monitoring PN function in 10 consecutive patients with atrial fibrillation undergoing cryoballoon pulmonary vein isolation.
Methods: A deflated neonatal blood pressure cuff filled with water was attached securely to the right costal margin using a velcro band placed circumferentially around the thorax. Pressure signals (PS) from this cuff were processed by a pressure transducer and displayed in mmHg as deflections from baseline. A multipolar electrode catheter was advanced to the superior vena cava/right atrial junction and was used to pace the right PN prior to and during isolation of the right superior pulmonary vein. Pacing amplitude during right PN pacing was varied randomly in 1-2 mA steps from 0 to 20 mA. An operator blinded to pacing amplitude and the PS was asked to assess DM by grading F/MP from 0 to 4+.
Results: The strength of DM graded by F/MP varied as a direct function of pacing amplitude (Spearman correlation 0.738, p by Pearson ≤0.001). Similarly, the amplitude of the PS varied as a direct function of pacing amplitude and correlated well with the strength of DM as assessed by F/MP (Spearman correlation 0.811, p by Pearson ≤0.001) Decreases in PS in response to decreased pacing output were sometimes seen earlier than was detected by F/MP.
CONCLUSION: This “hands-free” nonfluoroscopic method for monitoring PN function is an easy, reliable and sensitive way to assess DM during catheter ablation.
- © 2013 by American Heart Association, Inc.