Quantitative analysis of isolation area and rhythm outcome in patients with paroxysmal atrial fibrillation after circumferential pulmonary vein antrum isolation using the pace-and-ablate technique.

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 [24-96] 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 (log-rank 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 12 months, a larger ISA was associated with a significantly lower AF and macroreentrant tachycardia recurrence rate. ISA≥55% may thus serve as a predictor for long-term success after pulmonary vein antrum isolation.