Lesion Index-guided workflow for the treatment of paroxysmal atrial fibrillation is safe and effective - Final results from the LSI Workflow Study

Abstract

Background: Pulmonary vein isolation (PVI) ablation is a standard therapy for paroxysmal atrial fibrillation (PAF). Lesion Index (LSI) is a metric to guide radiofrequency (RF) ablation using the TactiCath Ablation Catheter, Sensor Enabled with the EnSite Cardiac Mapping System (Abbott).

Objective: This study (NCT-03906461) was designed to capture best practices using LSI-guided catheter ablation to treat PAF subjects in a real-world setting.

Methods: This prospective single-arm observational study enrolled 143 PAF subjects in the United States, Europe, and Japan undergoing de novo PVI with RF ablation. PVI lesions were assigned to 10 anatomically defined segments. Mean LSIs achieved for all lesions were analyzed. Follow-up was conducted between 3-6 months and 12 months after the procedure.

Results: Pulmonary veins were isolated in all subjects. The mean achieved LSI was 4.9, with lower values in Europe (4.4) and Japan (4.5) than the United States (5.5). First-pass success, defined as no gaps requiring touch-up ablation after 20 minutes post isolation, was achieved in 76.2% of subjects. Use of high LSI (≥5) resulted in shorter procedure, RF, and fluoroscopy times and fewer touch-up ablations compared to low LSI (<5). At 12 months, 99.3% of subjects were free from procedure- or device-related serious adverse events and 95.7% (112/117) (35.0% on antiarrhythmic drugs) were free from recurrence and/or a repeat ablation procedure for atrial fibrillation / atrial flutter / atrial tachycardia.

Conclusion: LSI-guided ablation strategies proved safe and effective despite differences in LSI workflows. Use of high LSI values resulted in shorter procedure, RF, and fluoroscopy times and fewer touch-up ablations compared to low LSI.

Keywords: Atrial fibrillation; Contact force; Lesion Index; Pulmonary vein isolation; Radiofrequency catheter ablation.

Graphical abstract

Figure 1

Lesion Index (LSI)–guided ablation using the EnSite System (Abbott). (Left) Voltage map created pre-ablation. (Middle) AutoMark lesions displayed using color settings according to achieved LSI (light pink ≥3.0, magenta ≥4.0, red ≥5.0). Real-time LSI is displayed on the EnSite system during ablation. (Right) Voltage map created post-ablation.

Figure 2

A: Reference points for the location of zone borders around the left (shaded circles A–D) and right (shaded circles E–H) pulmonary veins (PVs). Circle A: LSPV roof and anterior border; circle B: LSPV roof and posterior border; circle C: LIPV floor and posterior border; circle D: LIPV floor and anterior border; circle E: RSPV roof and posterior border; circle F: RSPV roof and anterior border; circle G: RIPV floor and anterior border; circle H: RIPV floor and posterior border. B: Numbered anatomical zones around the PVs. LIPV = left inferior pulmonary vein; LSPV = left superior pulmonary vein; RIPV = right inferior pulmonary vein; RSPV = right superior pulmonary vein.

Figure 3

Identified gaps, target Lesion Index (LSI), and achieved LSI by anatomical region. A: The number of subjects with gaps identified in each defined pulmonary vein region is noted. Note that in 3 subjects gaps were identified but unable to be isolated. Subjects may have experienced a reconnection in more than 1 zone. B: For each defined pulmonary vein region displayed in panel A, the mean ± standard deviation target LSI, the mean ± standard deviation achieved LSI, and the mean ± standard deviation minimum achieved LSI per subject for first-pass isolation (no gaps identified in the zone) are displayed. Target LSI, the desired LSI value for each lesion, was defined by the operator for each region in each subject. Achieved LSI for each lesion was included in the AutoMark data. Postprocedure, each lesion was categorized into a defined region. Abbreviations as in Figure 2.

Figure 4

Lesion-level characteristics. The mean and standard deviation for contact force, average power, and duration are included for each subgroup analyzed. LSI = Lesion Index.

Figure 5

Touch-up ablations. The number of subjects with pulmonary vein touch-up ablations performed during the index procedure, evaluated for each subgroup: by geography (bottom), by mean achieved Lesion Index (LSI) (middle), and by high or standard average power (top).