The feasibility of a Box isolation strategy for non-paroxysmal atrial fibrillation in elderly patients

• Main Authors: Satoshi Higuchi, MD, Hiroshi Sohara, MD, PhD, Yoshinori Nakamura, MD, PhD, Minoru Ihara, MD, PhD, Yoshio Yamaguchi, MD, PhD, Morio Shoda, MD, PhD, Nobuhisa Hagiwara, MD, PhD, Shutaro Satake, MD, PhD
• Format: Article
• Language: English
• Published: Wiley 2016-06-01
• Series: Journal of Arrhythmia
• Subjects: Atrial fibrillation; Catheter ablation; Box isolation; Elderly patient; Typical atrial flutter
• Online Access: http://www.sciencedirect.com/science/article/pii/S1880427616000351

Background: Catheter ablation of non-paroxysmal atrial fibrillation (non-PAF) is a therapeutic challenge especially in elderly patients. This study describes the feasibility of a posterior left atrium isolation as a substrate modification in addition to pulmonary vein isolation, the so-called Box isolation, for elderly patients with non-PAF. Methods: Two hundred twenty-nine consecutive patients who underwent Box isolations for drug-refractory non-PAF were divided into two groups according to their age; younger group comprising 175 patients aged <75 years and elderly group comprising 54 patients aged ≥75 years. Results: During 23.7±12.0 months of follow-up, the arrhythmia-free rates after one procedure were 53.1% in younger group versus 48.1% in elderly group (p=0.50). Following the second procedure, all patients had electrical conduction recoveries along the initial Box lesion. However, a complete Box re-isolation was highly established in both age groups (87.1% vs. 92.9%, respectively; p=1.00). Recurrence of macro-reentrant atrial tachycardia was mainly associated with the gaps through the initial Box lesion in both age groups (25.8% vs. 21.4%, p=1.00), but typical cavo-tricuspid isthmus (CTI) dependent atrial flutter was significantly observed in the elderly patients’ group only (all events were observed within 6 months after the initial procedure; 3.2% vs. 28.6%, p=0.009). After two procedures, the arrhythmia-free rates increased to 73.1% in younger group versus 66.7% in elderly group (p=0.38). The occurrence rate of procedural-related complications did not differ between the two age groups, and there were no life-threatening complications even in elderly patients. Conclusions: Box isolation of non-PAF is effective and safe even in elderly patients. A prophylactic CTI ablation combined with Box isolation might be feasible to improve the long-term outcome.