Local multifrequency impedance changes after radiofrequency ablation in human atria: potential use for tissue...

Area of Science:

• Cardiovascular Medicine
• Electrophysiology
• Biomedical Engineering

Background:

• Local impedance (LI) mapping offers advanced tissue characterization of the atria.
• Measuring LI at various frequencies explores intra- and extra-cellular compartments, aiding tissue integrity assessment.

Purpose of the Study:

• To characterize changes in local multifrequency impedance (LMI) in human atrial tissue post-radiofrequency ablation.
• To evaluate LMI's potential as a tool for atrial substrate characterization and monitoring ablation lesion quality.

Main Methods:

• Fifteen patients undergoing catheter ablation for atrial arrhythmias were studied.
• Local multifrequency impedance (LMI) was measured at multiple sites using electrocatheters before and after pulmonary vein isolation (PVI) via radiofrequency ablation.
• Offline analysis compared bipolar voltage and LMI values of blood, healthy, and ablated tissue, also analyzing cardiac cycle variations and catheter contact effects.

Main Results:

• Distinct LMI signatures were observed for blood pool, healthy myocardium, and post-ablated tissue (Z_PRE = 110±15 Ω, Z_POST = 90±10 Ω, Z_BLOOD = 90±8 Ω; p < 0.001).
• LMI cyclic changes exhibited an inverse relationship with contact force.
• These cyclic changes were more attenuated in post-ablated tissue (p < 0.001).

Conclusions:

• Local multifrequency impedance (LMI) successfully differentiates pre- from post-ablated atrial tissue.
• LMI demonstrates potential clinical utility for characterizing atrial substrate.
• This technique may aid in monitoring lesion quality for durable ablation outcomes.