Catheter settings and left atrial mapping
Electrophysiological studies and catheter ablation were performed under
general anesthesia using intravenous propofol at 5–10 ml as a bolus
injection followed by 0.5 ml/kg/hr as a maintenance dose. A ventilator
(HAMILTON C-1®; Hamilton Medical, Bonaduz,
Switzerland) in synchronized intermittent mandatory ventilation mode
with a respiratory rate of 12 breaths per min and tidal volume of 400 or
500 ml was used together with a supraglottic airway device
(i-gel®; Intersurgical Limited, Berkshire, UK). An
esophageal temperature probe (SensiTherm®; Abbott, St.
Paul MN, USA) was inserted to monitor esophageal temperature during RFA
at the left atrial posterior wall.
A 6-Fr decapolar electrode was inserted into the coronary sinus, while a
second 6-Fr decapolar electrode was placed in the right atrium.
Following a transseptal puncture at the fossa ovalis, one steerable long
sheath (Agilis® M curve; Abbott) was introduced into
the LA using a transseptal puncture technique.
Mapping in the left atrium and 4 PVs was then performed using
RHYTHMIA® (Boston Scientific) under right atrial
pacing rhythm (100 ppm) using the small basket catheter
(Orion®; Boston Scientific) via the steerable long
sheath. Criteria used for beat acceptance included stable cycle length,
stable timing difference between two reference electrodes placed in the
coronary sinus, respiratory gating, stable catheter location, and stable
catheter signal compared to adjacent points.