Effect of Charge Delivery on Thromboembolism During Radiofrequency Ablation in Canines

This study investigated whether delivering negative charge to catheter tips reduces thromboembolism during catheter ablation.

Radiofrequency (RF) ablation prevents atrial fibrillation that can cause stroke or death. However, ablation itself can cause stroke (2%) or silent ischemia (2% to 41%), possibly via particulate debris that embolizes after coagulum adherence to catheter surfaces. Coagulum formation on RF catheters can be prevented by applying negative charge, but it is unknown if charge reduces peripheral thromboembolism.

Paired (Charge ON vs. OFF) endocardial RF ablations were performed in 9 canines using nonirrigated RF catheters. Continuous negative charge was delivered via -100 μA of DC current applied to ablation catheter electrodes. Intracardiac echocardiography was used to navigate the catheter and to monitor coagulum formation. In a subset of 5 canines, microemboli flowing through polyester tubing between the femoral artery and vein (extracorporeal loop) were monitored with bubble counters and inline filter fabric. After each ablation, catheter-tip coagulum and blood particles deposited on the filters were quantified using photography and imaging software (ImageJ, U.S. National Institutes of Health, Bethesda, Maryland).

Negative charge significantly decreased the extracorporeal loop median filter area covered by particles (n = 19 pairs) by 10.2 mm² (p = 0.03), and decreased median filter particles by 349 (p = 0.03). Negative charge also decreased the percentage of the catheter tip surface area covered by coagulum (n = 39 pairs) by 7.2% (p = 0.03).

Negative charge delivery to ablation catheter tips during RF ablation can reduce particulate embolization material in an extracorporeal loop, and potentially reduce thromboembolic risk associated with RF ablation.