Introduction
Pulmonary vein isolation (PVI) is a widely accepted procedure for catheter ablation of patients with atrial fibrillation (AF). For a completion of the PVI, access to the left atrium (LA) is required, and a transseptal puncture has usually been performed. The procedure in the LA has a substantial risk of systemic embolisms including cerebral and myocardial infarctions1-2.
The PVI using a cryoballoon has emerged as an alternative ablation procedure tool for radiofrequency (RF) ablation and its safety and effectiveness have been proven3-4. However, thrombi and air embolic events during cryoballoon ablation have recently been reported2, 5. In terms of air embolic events during the procedure, the creation of procedure related micro air bubbles has been thought to be the most common factor6-7. The majority of micro air embolisms are silent, asymptomatic, and detected by brain magnetic resonance imaging after the procedure6, 8. On the other hand, a large amount of an air embolism during the catheter ablation procedure is rare, but could be life-threatening1-2. It is mainly caused by massive air intrusion through a long sheath located in the LA and is prone to occur at the time the intra LA pressure (LAP) drops to less than the atmospheric pressure1, 9.
Patients typically receive sedation during the PVI because the procedures take several hours and often are inflictive. Sedation of patients could inevitably result in an upper airway obstruction and subsequently provoke apnea and snoring, which could reduce the intra thoracic pressure and LAP. A decreased LAP to less than the atmospheric pressure increases the risk of air intrusion into the vasculature through a long sheath.
Adaptive servo-ventilation (ASV) (AutoSet CS; ResMed, Sydney) is a noninvasive positive pressure ventilation and is designed to treat sleep-disordered breathing10-11. It provides a positive expiratory airway pressure and inspiratory pressure support, and automatically adjusts the airway ventilation volume based on the analysis of the patient‘s breathing effort. Although the efficacy of the ASV therapy in patients with sleep-disordered breathing has been widely accepted, the accurate efficacy of ASV for the LAP in sedated patients remains unclear.
The aim of this study was to investigate the LAP in sedated patients undergoing a cryoballoon PVI and to clarify the impact of the ASV on the LAP during the procedure.