Background-We sought to determine the relationship between the size of the left atrial isolated surface area (ISA) after pulmonary vein antrum isolation for paroxysmal atrial fibrillation (AF) and rhythm outcome during a 12-month follow-up. Methods and Results-One hundred one consecutive patients with paroxysmal AF (mean age, 59±11 years; median [range] AF history, 36 months; mean left atrial size, 42±6 mm) were enrolled. The ISA was defined as the ratio of the total isolated antral surface area excluding the pulmonary veins to the sum of the total isolated antral surface area and the left atrial posterior wall surface area, while considering the individual characteristics of antral anatomy. All surface areas were assessed using the NavX system. Patients were divided into 4 groups according to ISA (group I: <50%; group II: 50 to <60%; group III: 60 to <70%; group IV: ≥70%). The average ISA for all patients was 59.2±11.6%. Subgroup analysis showed that ISA was 42.8±4.2% in group I (n=23), 54.2±3.0% in group II (n=23), 64.3±3.0% in group III (n=33), and 73.9±3.6% in group IV (n=22). After a 12-month follow-up period, 70% of patients in group I, 78% in group II, 97% in group III, and 100% in group IV were free from AF and atrial macroreentrant tachycardia. There was a significant difference between groups I and III, I and IV, II and III, and II and IV but not groups I and II and groups III and IV (logrank test P=0.024, 0.016, 0.037, 0.044, 0.584, and 0.500, respectively). Receiver operating characteristic curve analysis yielded an optimal cutoff value of 55% for ISA.
Conclusions-After
Methods
Patient SelectionThe study was conducted on 101 consecutive patients with highly symptomatic, medically refractory paroxysmal AF, who had been treated with PVAI between January and December 2009. Paroxysmal AF was defined as a self-terminating AF of <1 week duration.
Mapping and Ablation ProcedureBefore the procedure, transesophageal echocardiography was performed to exclude thrombus formation. Patients were studied under deep propofol sedation, breathing spontaneously. Standard electrode catheters were placed in the right ventricular apex and the coronary sinus, after which a single transseptal puncture was made. Unfractionated heparin was administered in bolus form immediately after the transseptal puncture to maintain an activated clotting time of >250 s. If AF occurred an external electrical cardioversion was performed to restore sinus rhythm. Mapping and ablation were performed using the NavX system (St. Jude Medical, Inc, St. Paul, MI) as a guide after integration of a 3-dimensional model of the left atrium (LA) and PV anatomy obtained from preinterventional computed tomography (CT), as described previously. 10 Before the ablation, the circular mapping catheter-reconstructed PV anatomies were aligned with the CT-PVs. Furthermore, the multipolar mapping catheter was replaced by a 4-mm M-curve irrigated tip ablation catheter (IBI Therapy Cooled Path; St Jude Medical, Inc). Fine adjustment of image integration was ach...