Pulmonary vein isolation using ablation index vs. CLOSE protocol with a surround flow ablation catheter

Area of Science:

• Electrophysiology
• Cardiology

Background:

• Pulmonary vein isolation (PVI) is a key treatment for atrial fibrillation (AF).
• The ablation index (AI) guides PVI, incorporating stability, contact force, time, and power.
• The CLOSE protocol combines AI with a ≤6 mm interlesion distance, with safety considerations for surround flow ablation catheters (STSF).

Purpose of the Study:

• To compare the safety and effectiveness of an AF ablation strategy using the AI alone versus the CLOSE protocol with STSF catheters.

Main Methods:

• A prospective study comparing two patient clusters: one treated with AI and the other with the CLOSE protocol.
• Procedural data, safety outcomes, and recurrence of atrial tachycardia (AT) or AF >30 seconds were collected.
• Anti-arrhythmic drugs (AAD) were stopped post-blanking period for 215 consecutive patients.

Main Results:

• Pulmonary vein isolation was achieved in all patients, with similar procedure and radiofrequency times between groups.
• The CLOSE protocol demonstrated higher first-pass isolation rates (left veins: 90% vs. 80%; right veins: 84% vs. 73%).
• Twelve-month freedom from AF/AT off AAD was significantly higher in the CLOSE group (79%) compared to the AI group (64%), particularly in paroxysmal AF patients. Major complications were similar between groups (2.1% vs. 2.5%).

Conclusions:

• The CLOSE protocol is more effective than AI alone for PVI, especially in paroxysmal AF.
• The study achieved a 79% freedom from AF/AT off AAD at 12 months.
• The STSF catheter is safe when used with conventional CLOSE protocol targets.