Effect of Mechanical Ventilation on Radiofrequency Ablation in Atrial Fibrillation

Radiofrequency ablation for the treatment of atrial fibrillation (AF) has recently been performed under general anesthesia with patients connected to a mechanical ventilator device. There are studies showing that whether patients are connected to spontaneous or controlled ventilation directly affects the results of the ablation procedure. In the ablation procedure, safe myocardial tissue contact of the catheter electrode determines predictable lesion size distribution and ultimately procedural success. Therefore, contact force has been a reliable marker in predicting the ability to deliver an effective transmural lesion. Catheter tip movement due to respiratory changes may lead to inadequate lesion formation, potentially resulting in AF recurrence. In the existing literature, high-frequency jet ventilation (HFJV) has been reported to increase catheter stability, improve tissue contact and reduce AF recurrence due to reduced thoracic motion. An alternative strategy was used by simulating very low tidal volume ventilation with high respiratory rate with a flow similar to HFJV with standard anesthesia devices.

The incidence of atrial fibrillation recurrence following catheter ablation depends on various patient-level factors and procedural techniques. An important determinant of success in AF ablation is the adequacy of the energy delivered to the cardiac tissue and the durability of pulmonary vein isolation (PVI). Approximately 20% of patients undergoing AF ablation require re-ablation within 12 months, regardless of technique. AF recurrence following ablation occurs mainly through pulmonary vein electrical reconnection, and the rate of ≥ 1 reconnected pulmonary vein during AF reablation is \>80%. Inadequate energy delivery and tissue heating due to insufficient contact or challenging anatomical locations during ablation is one of the main culprits of procedure failure in radiofrequency ablation (RFA). Therefore, efforts to improve the success of the PVI procedure include optimizing catheter stability and contact force. Thus, catheter force and stability are highly influenced by respiratory-induced thoracic movement, demonstrating the importance of controlled breathing for further ablation optimization. Fluoroscopy and ablation times during electroanatomic mapping-guided AF ablations have improved significantly with the use of controlled mechanical ventilation. To improve catheter contact, general anesthesia with controlled breathing has been used for better procedural success than conscious sedation.

To date, there are no randomized clinical trials in the literature demonstrating the superiority of one mode of ventilation over another during the ablation procedure. Low tidal volume, high respiratory rate (FCV, Flow Controlled Ventilation), pressure controlled mechanical ventilation (PCV), volume controlled mechanical ventilation (VCV), pressure controlled volume guaranteed mechanical ventilation (PRVC) can be applied with the mechanical ventilator equipment available in the anesthesiology and reanimation clinic of investigators' hospital. However, HFJV mechanical ventilator mode cannot be applied in general anesthesia patients in accordance with the facilities of investigators' hospital. In addition, there is no definite information in the literature about the superiority of any mode over the other for ablation procedure. Therefore, different mechanical ventilation modes are applied in ablation procedures in investigators' hospital according to the preferences of the practitioner. Investigators believe that there is a need for studies on the modes used in ablation procedures performed under general anesthesia.