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.