Procedures
Procedures were preferably performed under general anesthesia, or
conscious sedation if general anesthesia was not available.
Antiarrhythmic medications were neither discontinued prior to ablation,
nor administered during the procedures. After achieving
echography-guided femoral vein access, a 24-pole diagnostic catheter
(Woven Orbiter, Boston Scientific Inc.) was placed around the tricuspid
annulus with its distal part into the coronary sinus. If the initial
rhythm was AT, entrainment from both right and left atria (via coronary
sinus) was used to define AT origin. If the patient was in sinus rhythm,
atrial programmed stimulation with ramps was first used to induce AT. If
the left atrium (LA) was intended to map, transseptal puncture with a
conventional long sheath (SL1, Abbott Medical Inc., Chicago, IL) was
performed and intravenous heparin was administered to achieve a target
activated clotting time of 350-400 seconds. Steerable sheaths (Agilis,
Abbott Medical Inc.) were only used to improve catheter manipulation in
selected difficult cases.
Patients were included if AF was induced, or conversion from AT to AF
(or continuous AT circuit changes, considered equivalent to AF) happened
during the procedure, and no spontaneous re-conversion to a stable AT
occurred during the following 15 minutes. Also, patients with AF as
initial rhythm were included.