Conventional pulmonary vein isolation compared with the "box isolation" method: a randomized clinical trial.

Area of Science:

• Cardiology
• Electrophysiology
• Medical Devices

Background:

• Radiofrequency ablation for atrial fibrillation (AF) carries a risk of esophageal injury, particularly when targeting the posterior left atrium (LA).
• The box isolation technique aims to isolate the posterior LA and pulmonary veins without direct ablation on the posterior LA wall, potentially mitigating esophageal risks.

Purpose of the Study:

• To compare the acute and long-term efficacy of the box isolation method versus conventional circumferential pulmonary vein isolation (PVI) for catheter ablation of AF.
• To evaluate the success rate of achieving complete posterior LA isolation using the box isolation technique.

Main Methods:

• A pilot study involving 29 patients with drug-refractory AF undergoing catheter ablation.
• Sixteen patients (55%) were treated with the box isolation method, while 13 underwent standard circumferential PVI.
• AF recurrence was monitored using daily portable ECG home monitors over a mean follow-up of 10 months.

Main Results:

• Complete isolation of the posterior LA was achieved in only 19% of patients undergoing box isolation.
• The success rates for box isolation were 25% complete success, 38% improvement, and 37% failure.
• For standard PVI, success rates were 15% complete success, 62% improvement, and 23% failure, with no statistically significant difference between groups (p = 0.44).

Conclusions:

• The efficacy of box isolation for AF catheter ablation appears similar to conventional circumferential PVI in this pilot study.
• The box isolation method alone infrequently resulted in complete pulmonary vein isolation.
• Based on these findings, the box isolation strategy is not recommended.