PO-01-081 EPICARDIAL PHRENIC NERVE DEFLECTION DURING SINUS NODE MODIFICATION

Abstract

Endocardial catheter ablation for sinus node modification may be difficult due to right phrenic nerve location and risk of injury. Various strategies to displace the phrenic nerve from target ablation sites have been described previously, including saline infusion and balloon catheter insufflation, all within the epicardial space. To describe a strategy to avoid phrenic nerve injury during endocardial catheter ablation for sinus node modification using a steerable catheter. N/A A 33-year-old female with a history of Behcet’s disease and AF ablations but otherwise without structural heart disease developed symptomatic inappropriate sinus tachycardia (IST) recorded on her loop recorder. Her IST was refractory to multiple drugs including flecainide, sotalol, dofetilide, and ivabradine. She had previously undergone catheter ablation for sinus node modification, which was limited due to proximity of the phrenic nerve near the intended ablation target. She presented for a repeat catheter ablation with planned epicardial access for sinus node modification. The patient presented to the EP lab in sinus rhythm with rates in the 60s. Endocardial and epicardial access were obtained under general anesthesia. The ablation catheter was advanced into the superior vena cava and right atrium, and the IST activation map during isoproterenol infusion and sites of phrenic capture were annotated (Figure A). Using a steerable sheath and a non-irrigated 4mm catheter via the epicardial access, the phrenic nerve was deflected away from the sinus node. The proximity between the endocardial and epicardial catheters was confirmed on fluoroscopy (Figure B). The phrenic nerve was checked before and after each ablation lesion. A total of 11 lesions at 30W with target contact >10 grams and target impedance drop >10 ohms was delivered for a total of 333 seconds (Figure C). Following endocardial catheter ablation, her resting sinus rates decreased to 50s. Isoproterenol infusion challenge before and after the ablation revealed blunted response in her heart rate. Her phrenic nerve remained intact with appropriate diaphragm stimulation. The patient was resumed on sotalol and discharged. Endocardial catheter ablation for IST sinus node modification may be challenging due to the phrenic nerve. Epicardial access for phrenic nerve deflection may be required.