A steerable sheath (FlexCath, Medtronic, Minneapolis, Minnesota) was inserted into the LA over
an Amplatzer guidewire (Boston Scientific, Minneapolis, Minnesota), and Rimonabant cost
28-mm Arctic Front or Arctic Front Advance balloon (Medtronic) was used to perform cryoablation around the antrum of all 4 PVs using intracardiac ultrasound and fluoroscopic guidance. Cooling was performed to temperatures ranging between??41°C and??51°C. At?least 2 applications were delivered in the antrum of each vein. Right phrenic nerve pacing was performed using a circular catheter positioned in the superior vena cava. Following cryoapplication, the balloon was removed and a 3.5-mm catheter inserted to the LA to finalize incomplete lesions or add additional lines at
the operator’s discretion.
All redo procedures were performed using point-by-point RF ablation as described earlier. Mapping maneuvers as described previously were used to diagnose the mechanism of an induced arrhythmia 10?; ?11. PVs and all previously performed linear lesion sets were checked for conduction recovery. Conduction gaps in lines were ablated to achieve bidirectional conduction block. If patients presented in sinus rhythm (SR), arrhythmia induction was performed with burst pacing and intravenous isoproterenol. Focal or linear ablation and ablation of CFAEs in the left and right atrium were performed depending on the induced arrhythmias. Inducibility for atrial arrhythmias was reassessed at the end of the?procedure with burst pacing and intravenous isoproterenol.
Patients were followed up at our center or with referring cardiologists with regular Holter electrocardiography and 12-lead electrocardiography in case of symptoms. Referring cardiologists and primary care physicians were contacted for clinical follow-up if necessary. Recurrence was defined as any documented atrial arrhythmia lasting?≥30 s.
Continuous variables are presented as mean ± SD. Categorical variables are expressed as count (percentage). Differences of continuous and categorical variables were tested for statistical significance using Student t tests and Pearson chi-square tests, respectively. Recurrence curves were plotted using the Kaplan-Meier method, and the log-rank test was used to compare the 2 groups. No blanking period
was applied for Kaplan-Meier analysis. A 2-tailed p value?<0.05 was considered to indicate statistical significance. Data analysis was performed using IBM SPSS Statistics for Mac version 22.0 (IBM, Armonk, New York).<br />Results
Redo procedures were performed in 63 of 300 patients (21%), 297 ± 219 days following the index procedures. Persistent isolation of all PVs was demonstrated in 26 patients (9% of the 300 total patients and 41% of redo patients), forming the study population. Baseline and procedural characteristics are summarized in Table?1, and the ablation strategy at the index procedures is summarized in Figure?1. The indications for the index procedures were paroxysmal AF in 9 patients (35%) and persistent AF in 17 patients (65%). Recurrent AF was documented in?11 patients (42%; AF group) and organized AT in 15?patients (58%; AT group) leading to the redo procedures.