PO-01-200 UNIPOLAR SIGNAL MODIFICATION-GUIDED RADIOFREQUENCY ABLATION

Abstract

Listen

Translate article

Positive atrial unipolar signal modification (USM) during catheter ablation has been shown to reflect irreversible transmural lesions. To assess the relationship between tissue thickness, power modification, and lesion transmurality in radiofrequency ablation (RFA) guided by USM, and to compare the ablation time between ablation index (AI) guided RFA and USM-guided RFA. In-vivo: RFA single lesions guided by USM were created in the right and left atrium of Yorkshire swine using 30W-35W power. Lesions were assessed for depth, width, and transmurality. Secondary analysis stratifying for tissue thickness (thickness <3mm and thickness ≥3mm) was performed. In-human: in 5 consecutive patients undergoing RFA for paroxysmal atrial fibrillation guided by AI using 35-40W power, the time to USM was recorded and was compared with the real time needed for AI guided ablation (AI=380-550). USM were obtained using the PureEP System from BioSig Technologies for signal recordings. Unipolar ablation signals were collected and compared at high pass filter settings of 0.05Hz, 0.5Hz, 1.0Hz, and 5Hz. In-vivo: A total of 13 swine were used (weight 83±6kg) with a total of 50 ablations. Using 30-35W (n=50 lesions, contact-force =12±3g), time to USM was 6±2.2 seconds, impedance drop was 18±8 Ohm, and 90% of the lesions were transmural. Lesion dimensions were (shown in mean ± std in mm): tissue thickness 2±1.1mm, depth 1.95±0.6mm, and width 9.2±0.6mm. The average AI at USM in swine was 280±48. Secondary analysis demonstrated that in lesions with tissue-thickness <3mm (n=38; 1.5mm-2.5mm) transmurality was 100% for USM guided ablations, whereas in lesions with tissue-thickness ≥3mm (n=12; 3mm-5.5mm) transmurality was achieved only in 33% of the cases when guided by USM. In-humans: A total of 340 lesions were performed using 35-40W power. Mean ablation time (real time for AI guided ablation) was 24±9.5 seconds, whereas the USM were noted at a mean time of 8±3 seconds (delta of 18±11 seconds; p<0.001 for the comparison; Figure). For atrial tissue thickness <3mm, USM-guided ablation successfully resulted in transmural lesions. The time needed for ablation was very short and was less than one third of the time needed for AI guided ablations. Further studies are needed to find the optimal ablation settings for tissue thickness ≥3mm where current methods of using AI guided ablation might be too prolonged.