Personalized paroxysmal atrial fibrillation ablation by tailoring ablation index to the left atrial wall thickness: the ‘Ablate by-LAW’ single-centre study—a pilot study

Abstract

Aims To determine if adapting the ablation index (AI) to the left atrial wall thickness (LAWT), which is a determinant of lesion transmurality, is feasible, effective, and safe during paroxysmal atrial fibrillation (PAF) ablation. Methods and results Consecutive patients referred for PAF first ablation. Left atrial wall thickness three-dimensional maps were obtained from multidetector computed tomography and integrated into the CARTO navigation system. Left atrial wall thickness was categorized into 1 mm layers and AI was titrated to the LAWT. The ablation line was personalized to avoid thicker regions. Primary endpoints were acute efficacy and safety, and freedom from atrial fibrillation (AF) recurrences. Follow-up (FU) was scheduled at 1, 3, 6, and every 6 months thereafter. Ninety patients [60 (67%) male, age 58 ± 13 years] were included. Mean LAWT was 1.25 ± 0.62 mm. Mean AI was 366 ± 26 on the right pulmonary veins with a first-pass isolation in 84 (93%) patients and 380 ± 42 on the left pulmonary veins with first-pass in 87 (97%). Procedure time was 59 min (49–66); radiofrequency (RF) time 14 min (12.5–16); and fluoroscopy time 0.7 min (0.5–1.4). No major complication occurred. Eighty-four out of 90 (93.3%) patients were free of recurrence after a mean FU of 16 ± 4 months. Conclusion Personalized AF ablation, adapting the AI to LAWT allowed pulmonary vein isolation with low RF delivery, fluoroscopy, and procedure time while obtaining a high rate of first-pass isolation, in this patient population. Freedom from AF recurrences was as high as in more demanding ablation protocols. A multicentre trial is ongoing to evaluate reproducibility of these results.

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

“…12 Beyond the AI-guided approach including catheter-tip to tissue contact force, power and ablation duration patients with advanced AF may benefit from further personalized ablation strategies. Adapting the AI to the LA wall thickness may allow for even lower RF delivery, fluoroscopy, and procedure times while obtaining a high rate of AF-free survival as demonstrated by Teres et al 13 Compared to the AI-guided approach, temperature-guided AF ablation with the DT catheter was associated with a significantly longer mean procedure duration, significantly more RF applications, a significantly shorter total RF duration as well as significantly lower fluoroscopy doses. Prior studies using the DT catheter reported on even longer procedure duration (84-159 min), RF application-(18-21 min), and fluoroscopy times (9-13 min).…”

“…[7][8][9][10] Initial studies have demonstrated the feasibility and safety of a combined, AI-guided HPSD ablation approach for AF ablation using a conventional force-sensing equipped ablation catheter. [11][12][13] Using a power-controlled 50 W HPSD setting, a high irrigation-flow rate is required to prevent charring and thrombus formation. Thus, real-time temperature monitoring at the catheter tip is limited.…”

“…In parallel, an ablation index (AI)‐guided ablation strategy, including catheter‐tip to tissue contact force, power, and ablation duration in a weighted formula has been validated to predict lesion formation and to improve clinical outcome 7–10 . Initial studies have demonstrated the feasibility and safety of a combined, AI‐guided HPSD ablation approach for AF ablation using a conventional force‐sensing equipped ablation catheter 11–13 . Using a power‐controlled 50 W HPSD setting, a high irrigation‐flow rate is required to prevent charring and thrombus formation.…”

The effect of left atrial wall thickness and pulmonary vein sizes on the acute procedural success of atrial fibrillation ablation

“…Of note, a recent study showed that LAWT-tailored, individualized AI values might result in similarly good results, even with somewhat lower AI targets. On the other hand, this approach is time consuming, but does not seem to be better in efficacy or safety [43].…”

Relationship between the posterior atrial wall and the esophagus: Esophageal position during atrial fibrillation ablation

“…Catheter ablation was performed by the By-LAW method, 9 with patients under general anesthesia with high-frequency, low-volume ventilation. Oral anticoagulation was uninterrupted, and periprocedural anticoagulation was performed to achieve an activated clotting time >300 seconds.…”