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

Abstract

Background Neither the actual in vivo tissue temperatures reached with lesion size index (LSI)‐guided high‐power short‐duration (HPSD) ablation for atrial fibrillation nor the safety profile has been elucidated. Methods We conducted a porcine study (n = 7) in which, after 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 compared tissue temperatures reached during 50 W‐HPSD ablation with those reached during standard (30 W) ablation, both targeting an LSI of 5.0 (5–15 g contact force). Results Tmax (maximum tissue temperature when the thermocouple was located ≤5 mm from the catheter tip) reached during HPSD ablation was modestly higher than that reached during standard ablation (58.0 ± 10.1°C vs. 53.6 ± 9.2°C; p = .14) and peak tissue temperature correlated inversely with the distance between the catheter tip and the thermocouple, regardless of the power settings (HPSD: r = −0.63; standard: r = −0.66). Lethal temperature (≥50°C) reached 6.3 ± 1.8 s and 16.9 ± 16.1 s after the start of HPSD and standard ablation, respectively (p = .002), and it was best predicted at a catheter tip‐to‐thermocouple distance cut point of 2.8 and 5.3 mm, respectively. All lesions produced by HPSD ablation and by standard ablation were transmural. There was no difference between HPSD ablation and standard ablation in the esophageal injury rate (70% vs. 75%, p = .81), but the maximum distance from the esophageal adventitia to the injury site tended to be shorter (0.94 ± 0.29 mm vs. 1.40 ± 0.57 mm, respectively; p = .09). Conclusions Actual tissue temperatures reached with LSI‐guided HPSD ablation appear to be modestly higher, with a shorter distance between the catheter tip and thermocouple achieving lethal temperature, than those reached with standard ablation. HPSD ablation lasting <6 s may help minimize lethal thermal injury to the esophagus lying at a close distance.

Acute oesophageal safety and long-term follow-up of AI-guided high-power short-duration with 50 W for atrial fibrillation ablation

“… 31 Actual tissue temperatures with LSI-guided 50 W ablations appear to be higher than those with standard 30 W ablation measured in a porcine model with thermocouples. 32 With better predictable tissue ablation effects, collateral oesophageal injuries might be prevented without sacrificing ablation success due to insufficient ablation lesions at posterior wall with subsequent PV reconnection. Reduced ablation time per lesion possibly alleviates effects of catheter instability and instable contact force resulting in more homogeneous, transmural ablation sites.…”

High power short duration versus low power long duration ablation in patients with atrial fibrillation: A meta‐analysis of randomized trials

“…Therefore, HPSD, despite producing a less deep lesion, ensures transmural lesions and lower risk of extracardiac injury. Indeed, porcine studies observed transmural endocardial lesions and more superficial esophageal adventitia injury with HPSD compared with LPLD 10,26 . Power AF and Hi‐Lo HEAT trial showed that HPSD had a similarly low incidence of esophageal thermal injuries to LPLD ablation 13,16 …”

“…Recent technological advances have paved the way to novel ablation strategies 6–8 ; among these, high power (40–50 W) short duration (HPSD) has been proven to be a viable alternative in terms of efficacy and safety 9 . HPSD has been demonstrated to produce larger, more superficial lesions that should not increase complication rate 10,11 …”

Characteristics of tissue temperature during ablation with THERMOCOOL SMARTTOUCH SF versus TactiCath versus QDOT MICRO catheters (Qmode and Qmode+): An in vivo porcine study

“…3 Several catheter options have been clinically introduced to facilitate HPSD and vHPSD procedures, including the THERMOCOOL SMARTTOUCH SF (STSF) (Biosense Webster), TactiCath ablation catheter, sensor enabled (TactiCath) (Abbott, Inc.), and QDOT MICRO (Biosense Webster) catheters. While HPSD and vHPSD ablation using various catheters have demonstrated relatively shallow lesions with acceptable clinical effectiveness and safety profiles, [4][5][6][7][8] differences in irrigation flow rate, energy control method, ablation indices, and catheter tip design may influence biophysics and lesion geometries. Nevertheless, the exact impact of these catheters on tissue remains to be fully understood.…”

“…Our prior in vivo animal studies involving STSF, TactiCath, and QDOT MICRO catheters have explored tissue temperatures in epicardial venoatrial tissues and collateral tissue damage. [5][6][7] In light of this background, comparing tissue temperature dynamics during 50 W HPSD guided by ablation indices and 90 W/4 s vHPSD ablation may yield valuable insights into achieving more effective and safer lesions with HPSD and vHPSD ablation settings across various catheters. Therefore, the primary objective of this study was to assess the differences in in-vivo tissue temperature dynamics and collateral damage, including phrenic nerve injury and esophageal injury, during 50 W HPSD ablation guided by ablation index (AI) using the STSF and QDOT MICRO catheters and by lesion size index (LSI) using the TactiCath catheter, as well as 90 W/4 s vHPSD ablation using the QDOT MICRO catheter.…”