Impact of impedance decrease during radiofrequency current application for atrial fibrillation ablation on myocardial...

Area of Science:

• Cardiology
• Electrophysiology
• Medical Devices

Background:

• The clinical significance of impedance decrease during radiofrequency catheter ablation (RFCA) remains unclear.
• Understanding impedance changes is crucial for optimizing ablation efficacy and safety.

Purpose of the Study:

• To analyze the impact of impedance decrease during RFCA.
• To determine the optimal cutoff value of impedance decrease for predicting outcomes.

Main Methods:

• 34 patients undergoing atrial fibrillation (AF) ablation were analyzed (3264 lesions).
• Measured parameters included impedance decrease, contact force (CF), force-time integral (FTI), and derived indexes (PIT, PIFT).
• Cardiac troponin I (TrpI) levels and reconnection incidence were assessed; ROC analysis was used to predict reconnection.

Main Results:

• Force-time integral (FTI) and product of impedance decrease and application time (PIT) correlated with troponin I increase (ΔTrpI).
• The product of impedance decrease and FTI (PIFT) showed the strongest correlation with ΔTrpI (r² = .29, P = .0010).
• PIFT predicted reconnection with an area under the curve of 0.71, optimal cutoff 5200 (sensitivity 78%, specificity 63%).

Conclusions:

• The combination of contact force and impedance decrease is important for evaluating myocardial lesions.
• PIFT is a valuable index for predicting reconnection during RFCA for AF.