General anesthesia in spontaneous respiration with intravenous ketamine in patients undergoing pulsed-field ablation

Abstract Funding Acknowledgements Type of funding sources: None. Background Thermal ablation of atrial fibrillation (AF) by means of radiofrequency or cryo-balloon is usually performed under general anesthesia, deep sedation, or conscious sedation at operator’s discretion and based on the general condition of the patient. However, a standardized sedation protocol when performing a non-thermal ablation, such as pulsed-field ablation (PFA) through irreversible cellular electroporation, has not been well established. Purpose We report our preliminary experience of a general anesthesia in spontaneous respiration protocol with ketamine used at a high-volume center during ablation of AF with a new PFA system. Methods All consecutive patients (pts) undergoing AF ablation with PFA at our center were included. Our sedation protocol consists of intravenous administration of midazolam (1+1 mg), fentanyl (25+25+25+25 mcg/kg) at low doses before local anesthesia with lidocaine (200mg) administration. Patients underwent sedation under spontaneous respiration by administering oxygen (4-6 l/min) through a face mask with nasal cannula. Local anesthesia was performed before the percutaneous femoral venous access. Soon after the trans-septal puncture, heparin (1 mg/kg) and atropine (1 mg, to mitigate anticipated bradycardia) were injected, followed by a second bolus of midazolam (1 mg). Ketamine adjunct (1 mg/kg) was then injected about 5 minutes before the first PFA delivery which was titrated to effect based on patient’s condition, response and changes in vital signs (total ketamine adjunction of 2 mg/kg). For quantitative assessment the Numeric Rating Scale for Pain (NRS) was applied. For qualitative assessment a 3-levels satisfaction evaluation was retrieved. The ablation endpoint was PVI as assessed by entrance and exit block. Results Forty-two pts were included in this analysis (mean age of 66±9 years,72% were male, CHA2DS2VASc score=2 [IQR 1–3], median body mass index 24[20-48]kg/m2, 35% had respiratory diseases – e.g. asthma, OSAS, COPD –). At baseline, before sedation, mean systolic blood pressure was 140.5+20.1mmHg and mean oxygen saturation was 97.9+2.1%. PVI was achieved in all the patients. The number of PFA applications to reach PVI was 33.4+3 (time to PVI = 25+4min). In two cases additional PFA lesion sets were deployed outside the PVs. Lab occupancy time was 122±32min, skin-to-skin time was 78±35min and fluoroscopy time was 23±14min. All the patients achieved