Sites With Small Impedance Decrease During Catheter Ablation for Atrial Fibrillation Are Associated With Recovery of...

Area of Science:

• Electrophysiology
• Cardiac Ablation
• Atrial Fibrillation Treatment

Background:

• Pulmonary vein isolation (PVI) durability is crucial for successful atrial fibrillation (AF) ablation.
• Current markers of successful ablation focus on acute conduction block, but better indicators for long-term success are needed.
• Local impedance decrease during ablation is a real-time indicator of tissue heating and lesion formation.

Purpose of the Study:

• To assess the correlation between impedance decrease during AF ablation and the durability of pulmonary vein (PV) isolation.
• To determine if impedance changes predict PV conduction recovery during subsequent procedures.

Main Methods:

• 167 patients undergoing first-time AF ablation had impedance changes recorded during radiofrequency ablation.
• Redo procedures were performed in 28 patients to identify sites of PV conduction recovery.
• Impedance changes at initial ablation sites were correlated with identified PV reconnections.

Main Results:

• 19 sites of PV conduction recovery were identified in 28 redo procedures.
• 89% of recovered PV conduction sites had an impedance decrease <10 ohms during the initial ablation.
• Regions with impedance decrease <10 ohms showed significantly higher rates of conduction recovery (37% vs. 1.5%) and larger ablation areas (21.9 mm vs. 11.5 mm).

Conclusions:

• Recovered PV conduction is common in areas where initial ablation resulted in impedance decrease <10 ohms.
• Impedance monitoring during ablation may serve as a valuable tool to predict and potentially improve the durability of PVI.