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.