Dynamic Ranges of Contact Force During Radiofrequency Ablation

Abstract

ABSTRACT. The aim was to assess the dynamic range for contact force (CF df ) in order to achieve an effective lesion according to anatomic variables under conscious sedation. We retrospectively studied 674 radiofrequency (RF) lesions (21 procedures) at Kingston General Hospital. Consecutive patients employing a CF catheter were recruited. A force-sensing catheter was used to continuously record CF data and force-time integral (FTI) during each lesion. The CF df represents the difference between the highest and lowest recorded contact force for each RF application. Out of 674 lesions examined, we included 438 (65%). The CF df was significantly greater in the left atrium than in the right (36.6±20.3 versus 28.7±16.4, po0.01). Except in the cavotricuspid isthmus, the FTI lesions equal or are more than 400 g/s required higher CF df in all anatomical locations, and these differences reached statistical difference on the right atrial free wall, left atrial posterior wall, and right pulmonary vein antrum (p ¼ 0.011, 0.007, and o0.001). Yet, higher CF df is an independent predictor for less successful lesions in stepwise regression model. Left atrial enlargement above 46 mm was associated with lower CF df , CF av , and CF max (p ¼ 0.04, o0.001, and 0.02 respectively). This study represents the first detailed assessment of CF df in conscious sedation patients. Significant variations in the CF df were associated with different anatomic locations. We found that the greater the dynamic range the less likely the lesion would reach 400 g/s. Smaller atria were associated with higher dynamic ranges and greater peak and average forces.KEYWORDS. Average contact force, dynamic range for contact force, force time integral, maximum contact force, radiofrequency ablation.