Abstract 541 Validation of a New Ablation Index Protocol for Left Atrial Linear Ablation

Background

Standardized contiguous and optimized radiofrequency ablation encircling ipsilateral pulmonary veins (PV) with high incidence of first-pass isolation has been established with the CLOSE protocol. In this study, we evaluated the acute outcome of a specific ablation index protocol for left atrial (LA) linear ablation.

Methods

This prospective study comprised 100 patients (68 ±9 years, male: 57 %) undergoing de-novo ablation for persistent atrial fibrillation (AF) or patients requiring substrate ablation beyond PV isolation. A small pre-study including 10 patients was performed to evaluate appropriate ablation indices. We then hypothesized that point-by-point ablation with an ablation index of 600 for the anterior line and 500 for the roof line and an interlesion distance <6mm will result in a high rate of first-pass block. Touch-up ablation was performed in case of incomplete line block. Line integrity was evaluated with a high-density mapping catheter (Pentaray) and the coherent activation mapping tool (CARTO3 V7) during LAA pacing and differential pacing maneuver.

Results

First-pass block of the roof line was achieved in 89 (95 %) patients, while another 4 (4 %) patients required additional touch-up ablation to complete the line, resulting in a total of 93 (99 %) blocked roof lines. A first-pass anterior line block was observed in 60 (70 %) patients. An additional 19 (22 %) patients required touch-up ablation for block achievement, resulting in a total of 79 (92 %) blocked anterior lines. For the anterior line, the Bachmann bundle insertion was identified as the predominant location of gaps. The mean ablation index of roof line ablation was 513 ±13 and 610 ±14 in anterior line ablation. The mean overall procedure and fluoroscopy time was 137 ±31 min and 6.6 ±3.9 min, respectively. The mean RF ablation time for roof line was 8 ±5.1 min and for anterior line 14 ±5.7 min. Baseline rhythm was AF in 53 patients, which terminated by linear ablation in 16 (30%) patients. After a mean follow up time of 13 months, 62 of 92 patients (68%) remained in stable sinus rhythm with a large gender gap in favor of male patients (male 76%, female 54%, p = 0.02).

Conclusions

This new standardized Ablation Index protocol accomplishes first-pass block of left atrial linear lesions in the vast majority of patients. Furthermore, with additional touch-ablation at gap sites, line block was achieved in almost all patients. In terms of long-term durability, this strategy showed high 1-year follow-up success.

Clin Res Cardiol (2022). https://doi.org/10.1007/s00392-022-02002-5
Validation of a New Ablation Index Protocol for Left Atrial Linear Ablation
R. Spittler¹, E. Hambalek¹, T. Konrad¹, L. Rudolph², J. Zimmer², H. Mollnau¹, A. Marx¹, B. M. Quesada Ocete¹, P. M. G. Seidel¹, A. Dalmer¹, T. Rostock¹
¹Kardiologie II - Rhythmologie, Universitätsmedizin der Johannes Gutenberg-Universität Mainz, Mainz; ²Geschäftsbereich Biosense Webster, Johnson & Johnson Medical GmbH, Norderstedt;
Background Standardized contiguous and optimized radiofrequency ablation encircling ipsilateral pulmonary veins (PV) with high incidence of first-pass isolation has been established with the CLOSE protocol. In this study, we evaluated the acute outcome of a specific ablation index protocol for left atrial (LA) linear ablation. Methods This prospective study comprised 100 patients (68 ±9 years, male: 57 %) undergoing de-novo ablation for persistent atrial fibrillation (AF) or patients requiring substrate ablation beyond PV isolation. A small pre-study including 10 patients was performed to evaluate appropriate ablation indices. We then hypothesized that point-by-point ablation with an ablation index of 600 for the anterior line and 500 for the roof line and an interlesion distance <6mm will result in a high rate of first-pass block. Touch-up ablation was performed in case of incomplete line block. Line integrity was evaluated with a high-density mapping catheter (Pentaray) and the coherent activation mapping tool (CARTO3 V7) during LAA pacing and differential pacing maneuver. Results First-pass block of the roof line was achieved in 89 (95 %) patients, while another 4 (4 %) patients required additional touch-up ablation to complete the line, resulting in a total of 93 (99 %) blocked roof lines. A first-pass anterior line block was observed in 60 (70 %) patients. An additional 19 (22 %) patients required touch-up ablation for block achievement, resulting in a total of 79 (92 %) blocked anterior lines. For the anterior line, the Bachmann bundle insertion was identified as the predominant location of gaps. The mean ablation index of roof line ablation was 513 ±13 and 610 ±14 in anterior line ablation. The mean overall procedure and fluoroscopy time was 137 ±31 min and 6.6 ±3.9 min, respectively. The mean RF ablation time for roof line was 8 ±5.1 min and for anterior line 14 ±5.7 min. Baseline rhythm was AF in 53 patients, which terminated by linear ablation in 16 (30%) patients. After a mean follow up time of 13 months, 62 of 92 patients (68%) remained in stable sinus rhythm with a large gender gap in favor of male patients (male 76%, female 54%, p = 0.02). Conclusions This new standardized Ablation Index protocol accomplishes first-pass block of left atrial linear lesions in the vast majority of patients. Furthermore, with additional touch-ablation at gap sites, line block was achieved in almost all patients. In terms of long-term durability, this strategy showed high 1-year follow-up success.
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