Actual tissue temperature during ablation index‐guided high‐power short‐duration ablation versus standard ablation: Implications in terms of the efficacy and safety of atrial fibrillation ablation

Abstract

Background: Actual in vivo tissue temperatures and the safety profile during highpower short-duration (HPSD) ablation of atrial fibrillation have not been clarified. Methods:We conducted an animal study in which, after a right thoracotomy, we implanted 6-8 thermocouples epicardially in the superior vena cava, right pulmonary vein, and esophagus close to the inferior vena cava. We recorded tissue temperatures during a 50 W-HPSD ablation and 30 W-standard ablation targeting an ablation index (AI) of 400 (5-15 g contact force).Results: Maximum tissue temperatures reached with HSPD ablation were significantly higher than that reached with standard ablation (62.7 ± 12.5 vs. 52.7 ± 11.4°C, p = 0.033) and correlated inversely with the distance between the catheter tip and thermocouple, regardless of the power settings (HPSD: r = −0.71; standard: r = −0.64). Achievement of lethal temperatures (≥50°C) was within 7.6 ± 3.6 and 12.1 ± 4.1 s after HPSD and standard ablation, respectively (p = 0.003), and was best predicted at cutoff points of 5.2 and 4.4 mm, respectively. All HPSD ablation lesions were transmural, but 19.2% of the standard ablation lesions were not (p = 0.011). There was no difference between HPSD and standard ablation regarding the esophageal injury rate (30% vs. 33.3%, p > 0.99), with the injury appearing to be related to the short distance from the catheter tip.Conclusions: Actual tissue temperatures reached with AI-guided HPSD ablation appeared to be higher with a greater distance between the catheter tip and target tissue than those with standard ablation. HPSD ablation for <7 s may help prevent collateral tissue injury when ablating within a close distance.

Direct comparison of two 50 W high power short duration approaches—Temperature‐ versus ablation index‐guided radiofrequency ablation for atrial fibrillation

“…During the observation period of 6 months, no evidence for esophageal injury was reported irrespective of the HPSD approach. Prior HPSD studies reported on very low esophageal injury rates, too 19–22 . The AI‐HP ESO‐I study by Chen et al demonstrated that an AI‐guided HPSD 50 W approach appears to be safe concerning the risk for esophageal injuries 22 …”

“…Prior HPSD studies reported on very low esophageal injury rates, too. [19][20][21][22] The AI-HP ESO-I study by Chen et al demonstrated that an AI-guided HPSD 50 W approach appears to be safe concerning the risk for esophageal injuries. 22…”

In vivo tissue temperature during lesion size index‐guided 50W ablation versus 30W ablation: A porcine study

“…Several in vitro and ex vivo animal studies have also suggested that the application of this strategy can restrict conductive heating and increase resistive heating to allow targeted heating of the atrial wall, reducing the risk of collateral damage 3–6 . Nonetheless, in a recent in vivo porcine study, we found tissue temperatures to be higher during ablation index (AI)‐guided 50 W‐HPSD ablation than during 30 W ablation, and we found mild collateral damage to the phrenic nerve and esophagus even with 50 W‐HPSD ablation 7 . The lesion size index (LSI), which incorporates contact force (CF), time, and power, has been also used to optimize lesion formation in AF ablation, but in vivo preclinical data are lacking, particularly with respect to 50 W‐HPSD ablation.…”

Ablation index-guided high-power ablation for superior vena cava isolation in patients with atrial fibrillation

“…Ablation index-guided high-power ablation strategy is a combined ablation technique, which incorporates ideal ablation parameters into high-power ablation and makes the ablation procedure safer and more effective ( 10 – 12 ). On one hand, it uses high-power to achieve transmural lesions; on the other hand, limits the collateral damages.…”

“…The ablation index (AI), which weighs contact force (CF), radiofrequency time, and applied power, has been shown to aid in the creation of long-lasting ablation lesions (7)(8)(9). There are several studies, which applied AI-guided high-power ablation strategy in atrial fibrillation (AF) ablation and had been validated to improve clinical outcomes after ablation (10)(11)(12).…”