Oesophageal safety in voltage-guided atrial fibrillation ablation using ablation index or contact force only: a prospective comparison

CLOSE protocol versus lower ablation index value for paroxysmal atrial fibrillation: A randomized noninferior clinical trial

INTRODUCTION

The optimized ablation index (AI) value for catheter ablation of atrial fibrillation (AF) remains to be defined. We aimed to compare the efficacy and safety of CLOSE protocol and lower AI protocol in paroxysmal AF.

METHODS AND RESULTS

Patients with symptomatic, drug-resistant paroxysmal AF for first ablation were prospectively enrolled from September 2020 to January 2022. The patients were randomly divided into CLOSE group (AI ≥ 550 for anterior/roof segments and ≥400 for posterior/inferior segments) and lower AI group (AI ≥ 450 for anterior/roof segments and ≥350 for posterior/inferior segments). First-pass isolation, acute pulmonary vein (PV) reconnections, 1-year arrhythmia recurrence, and major complications were assessed. Of the 270 enrolled patients, 238 completed 1-year follow-up (118 in CLOSE group and 120 in lower AI group). First-pass isolation in left PVs was higher in CLOSE group (71.2% vs. 53.3%, p = .005). Acute PV reconnections were comparable between groups (9.3% vs. 14.2%, p = .246). At 1 year, 86.4% in CLOSE group versus 81.7% in lower AI group were free from atrial arrhythmia (log rank p = .334). The proportion difference was -4.8% (95% CI: -14.1% to 4.6%), and p = .475 for noninferiority. Stroke occurred in four patients of lower AI group, and no cardiac tamponade, atrioesophageal fistula, major bleeding or death occurred post procedure.

CONCLUSION

For patients with paroxysmal AF and treated by AI-guided PV ablation, lower AI is not noninferior to CLOSE protocol.

Higher power short duration vs. lower power longer duration posterior wall ablation for atrial fibrillation and oesophageal injury outcomes: a prospective multi-centre randomized controlled study (Hi-Lo HEAT trial)

AIMS

Radiofrequency (RF) ablation for pulmonary vein isolation (PVI) in atrial fibrillation (AF) is associated with the risk of oesophageal thermal injury (ETI). Higher power short duration (HPSD) ablation results in preferential local resistive heating over distal conductive heating. Although HPSD has become increasingly common, no randomized study has compared ETI risk with conventional lower power longer duration (LPLD) ablation. This study aims to compare HPSD vs. LPLD ablation on ETI risk.

METHODS AND RESULTS

Eighty-eight patients were randomized 1:1 to HPSD or LPLD posterior wall (PW) ablation. Posterior wall ablation was 40 W (HPSD group) or 25 W (LPLD group), with target AI (ablation index) 400/LSI (lesion size index) 4. Anterior wall ablation was 40-50 W, with a target AI 500-550/LSI 5-5.5. Endoscopy was performed on Day 1. The primary endpoint was ETI incidence. The mean age was 61 ± 9 years (31% females). The incidence of ETI (superficial ulcers n = 4) was 4.5%, with equal occurrence in HPSD and LPLD (P = 1.0). There was no difference in the median value of maximal oesophageal temperature (HPSD 38.6°C vs. LPLD 38.7°C, P = 0.43), or the median number of lesions per patient with temperature rise above 39°C (HPSD 1.5 vs. LPLD 2, P = 0.93). Radiofrequency ablation time (23.8 vs. 29.7 min, P < 0.01), PVI duration (46.5 vs. 59 min, P = 0.01), and procedure duration (133 vs. 150 min, P = 0.05) were reduced in HPSD. After a median follow-up of 12 months, AF recurrence was lower in HPSD (15.9% vs. LPLD 34.1%; hazard ratio 0.42, log-rank P = 0.04).

CONCLUSION

Higher power short duration ablation was associated with similarly low rates of ETI and shorter total/PVI RF ablation times when compared with LPLD ablation. Higher power short duration ablation is a safe and efficacious approach to PVI.