Left Atrial Appendage Conduction Jump for Real-Time Evaluation of Conduction Block Over the Anterior Mitral Annulus Line

Initial real-world data on catheter ablation in patients with persistent atrial fibrillation using the novel lattice-tip focal pulsed-field ablation catheter

AIMS

Technological advancements have contributed to the enhanced precision and lesion flexibility in pulsed-field ablation (PFA) by integrating a three-dimensional mapping system combined with a point-by-point ablation strategy. Data regarding the feasibility of this technology remain limited to some clinical trials. This study aims to elucidate initial real-world data on catheter ablation utilizing a lattice-tip focal PFA/radiofrequency ablation (RFA) catheter in patients with persistent atrial fibrillation (AF).

METHODS AND RESULTS

Consecutive patients who underwent catheter ablation for persistent AF via the lattice-tip PFA/RFA catheter were enrolled. We evaluated acute procedural data including periprocedural data as well as the clinical follow-up within a 90-day blanking period. In total, 28 patients with persistent AF underwent AF ablation either under general anaesthesia (n = 6) or deep sedation (n = 22). In all patients, pulmonary vein isolation was successfully achieved. Additional linear ablations were conducted in 21 patients (78%) with a combination of successful anterior line (n = 13, 46%) and roof line (n = 19, 68%). The median procedural and fluoroscopic times were 97 (interquartile range, IQR: 80-114) min and 8.5 (IQR: 7.2-9.5) min, respectively. A total of 27 patients (96%) were interviewed during the follow-up within the blanking period, and early recurrent AF was documented in four patients (15%) including one case of recurrent AF during the hospital stay. Neither major nor minor procedural complication occurred.

CONCLUSION

In terms of real-world data, our data confirmed AF ablation feasibility utilizing the lattice-tip focal PFA/RFA catheter in patients with persistent AF.

Extended early meets late for assessment of conduction block along an ablation line

PURPOSE

The purpose of the study was to investigate the usefulness of the extended early meets late (EEML) feature of the HD Coloring software for confirmation of bidirectional block along an ablation line.

METHODS

A single-center prospective observational study of consecutive patients with atypical atrial flutter or persistent atrial fibrillation submitted to catheter ablation including linear lesions from January 2019 to June 2020, with confirmation of bidirectional block across ablation lines assessed with the feature EEML and a multipolar catheter was conducted. Patients were divided into two groups - those with versus those without bidirectional block - and different EEML thresholds were analyzed to assess which one had the better sensitivity and specificity to predict block.

RESULTS

During the 24-month enrollment period, a total of 94 patients were included (50% males, mean age of 64 ± 10 years, 60% with structural heart disease) - 55 patients with versus 39 patients without confirmed a bidirectional block. Activation maps were performed during atrial pacing, with a median number of 1340 (interquartile range 1135-2060) points acquired in 11 ± 3 min, and a mean mapped cycle length of 287 ± 51 ms. The EEML feature was highly useful in detecting bidirectional block along ablation lines, with a 25% threshold value showing the highest discriminative performance (area under the curve of 0.93), 95% sensitivity and 92% specificity in predicting block.

CONCLUSIONS

The EEML feature of the HD Coloring software is a useful addition to the CARTO mapping system for assessment of block across an ablation line. The threshold value of 25% is the most accurate.

Ablation Index-guided high-power (50 W) short-duration for left atrial anterior and roofline ablation: Feasibility, procedural data, and lesion analysis (AI High-Power Linear Ablation)

OBJECTIVES

To evaluate the feasibility, procedural data, and lesion characteristics of the anterior line (AL) and roofline (RL) ablation by using ablation index (AI)-guided high power (50 W) among patients with recurrent atrial fibrillation (AF) or atrial tachycardia (AT) after pulmonary vein isolation (PVI).

METHODS

Data from 35 consecutive patients with macro-reentrant left atrial tachycardia or substrate at the left atrium anterior wall or roof after previous PVI were collected. Ablation power was set to 50 W, targeting AI 500 for AL and 400 for RL. The first-pass conduction block (FPB) was evaluated. The AL was arbitrarily divided into three (caudal, middle, and cranial) segments to analyze the location of conduction gaps in non-FPB patients.

RESULTS

A total of 32 AL and 17 RL were deployed and FPB was achieved in 24 (75%) and 14 (82%) of them, respectively. In the non-FPB group, the most frequent gap location along the AL was the middle third. The final block of AL was achieved in 97%, and the block of RL was achieved in 100%. The radiofrequency (RF) ablation time was short (2.9 ± 0.8 min for AL and 46.2 ± 15.6 s for RL). For AL, the female gender was significantly more frequent in FPB than in non-FPB patients (p = .028); patients with non-FPB were associated with significantly longer RF time as compared to patients with FPB (204 ± 47 s vs. 161 ± 41 s; p = .02). No procedural complications occurred.

CONCLUSION

AI-guided high-power (50 W) ablation appears to be a feasible, effective, and fast technique for AL and RL ablation.

Comparison of the anterior and posterior mitral isthmus ablation lines in patients with perimitral annulus flutter or persistent atrial fibrillation

BACKGROUND

Catheter ablation of left atrial linear lesions is an effective treatment option for perimitral flutter and is often used as a substrate modification approach for persistent atrial fibrillation. The two most popular mitral isthmus lines are those of the anterior or the posterior mitral isthmus. A comparison of these two mitral isthmus ablation approaches is still pending.

METHODS

Patients undergoing catheter ablation either at the anterior or the posterior mitral isthmus were included. Procedural success, conduction block, procedure durations, complications, and the necessity of a coronary sinus ablation were analyzed.

RESULTS

We investigated 80 consecutive patients, 40 (50%) with an anterior and 40 (50%) with a posterior mitral isthmus line. Twenty (25.0%) patients had perimitral annulus flutter; the remainder of the patients had persistent atrial fibrillation. Bidirectional conduction block was achieved in the same proportion in the anterior group (36; 90.0%) as it was in the posterior group (30; 75.0%) (statistically insignificant). Duration of procedure (18 ± 12 vs. 34 ± 24 min, p = 0.001), radiofrequency application (11 ± 7 vs. 18 ± 11 min, p = 0.004), and fluoroscopy (2 ± 2 vs. 8 ± 8 min, p < 0.001) values were all significantly lower in the anterior group. Only patients in the posterior line group had to be ablated via the coronary sinus 24 (60.0 %).

CONCLUSIONS

Ablation at the anterior mitral isthmus shows the same success rate as the posterior mitral isthmus does. Catheter ablation at the anterior mitral isthmus is associated with significantly shorter procedure durations without the need of a coronary sinus ablation.