Acute and long-term efficacy of ablation index-guided higher power shorter duration ablation in patients with atrial fibrillation: A prospective registry

Tailored ablation index based on left atrial wall thickness assessed by computed tomography for pulmonary vein isolation in patients with atrial fibrillation

INTRODUCTION

Although left atrial wall thickness (LAWT) is known to be varied, a fixed target Ablation Index (AI) based pulmonary vein isolation (PVI) has been suggested in catheter ablation for atrial fibrillation (AF). We aimed to evaluate the efficacy and safety of PVI applying tailored AI based on LAWT assessed by cardiac computed tomography (CT).

METHODS

The thick segment was defined as the segment including ≥LAWT grade 3 (≥1.5 mm). The fixed AI strategy was defined as AI targets were 450 on the anterior/roof segments and 350 on the posterior/inferior/carina segments regardless of LAWT. The tailored AI strategy consisted of AI increasing the targets to 500 on the anterior/roof segments and to 400 on the posterior/inferior/carina segments when ablating the thick segment. After PVI, acute pulmonary vein (PV) reconnection, defined by the composite of residual potential and early reconnection, was evaluated.

RESULTS

A total of 156 patients (paroxysmal AF 72%) were consecutively included (86 for the fixed AI group and 70 for the tailored AI group). The tailored AI group showed a significantly lower rate of segments with acute PV reconnection than the fixed AI group (8% vs. 5%, p = .007). The tailored AI group showed a trend for shorter ablation time for PVI. One-year AF/atrial tachycardia free survival rate was similar in two groups (87.2% in the fixed AI group and 90.0% in the tailored AI group, p = .606).

CONCLUSION

Applying tailored AI based on the LAWT was a feasible and effective strategy to reduce acute PV reconnection after PVI.

Network meta-analysis and systematic review comparing efficacy and safety between very high power short duration, high power short duration, and conventional radiofrequency ablation of atrial fibrillation

BACKGROUND

High-power short-duration (HPSD) atrial fibrillation (AF) ablation with a power of 40-50 W was proved to be safe and effective. Very high-power short-duration (vHPSD) AF ablation is a novel method using >50 W to obtain more durable AF ablation. This study aimed to evaluate the efficacy and safety of vHPSD ablation compared with HPSD ablation and conventional power ablation.

METHODS

A literature search for studies that reported AF ablation outcomes, including short-term freedom from atrial arrhythmia, first-pass isolation (FPI) rate, procedure time, and major complications, was conducted utilizing MEDLINE, EMBASE, and Cochrane databases. All relevant studies were included in this analysis. A random-effects model of network meta-analysis and surface under cumulative ranking curve (SUCRA) were used to rank the treatment for all outcomes.

RESULTS

A total of 29 studies with 9721 patients were included in the analysis. According to the SUCRA analysis, HPSD ablation had the highest probability of maintaining sinus rhythm. Point estimation showed an odds ratio of 1.5 (95% confidence interval [CI]: 1.2-1.9) between HPSD ablation and conventional power ablation and an odds ratio of 1.3 (95% CI: 0.78-2.2) between vHPSD ablation and conventional power ablation. While the odds ratio of FPI between HPSD ablation and conventional power ablation was 3.6 (95% CI: 1.5-8.9), the odds ratio between vHPSD ablation and conventional power ablation was 2.2 (95% CI: 0.61-8.6). The procedure times of vHPSD and HPSD ablations were comparable and, therefore, shorter than that of conventional power ablation. Major complications were low in all techniques.

CONCLUSION

vHPSD ablation did not yield higher efficacy than HPSD ablation and conventional power ablation. With the safety concern, vHPSD ablation outcomes were comparable with those of other techniques.

Ablation index-guided high-power ablation for superior vena cava isolation in patients with atrial fibrillation

Background

The strategy of ablation index (AI)-guided high-power ablation seems to be a novel strategy for performing pulmonary vein isolation (PVI). An AI-guided high-power ablation strategy was used in this study to determine whether superior vena cava isolation (SVCI) after PVI was feasible and safe for patients with AF.

Methods

Data from 53 patients with AF were collected. Mapping and ablation of SVC were performed. The applied power was set at 45 W and the procedure was guided by AI. The SVC was divided into six segments in a cranial view. The RF applications and AI values in different segments were compared and analyzed. Using receiver operating characteristic (ROC) analysis, the diagnostic accuracy of AI value for predicting segment block was evaluated.

Results

Electrical SVCIs were successfully achieved in all patients. SVCI was performed by segment ablation in most cases, with RF applications in different segments. The mean AI value in non-lateral walls was higher than that of the lateral wall (392 ± 28 vs. 371 ± 37, P < 0.001). Acutely blocked sites had significantly larger AI values compared with no-blocked sites (390 ± 30 vs. 343 ± 23, P < 0.001). The optimal AI cut-off value for non-lateral segments was 379 (sensitivity: 75.9%, specificity: 100%) and for lateral segments was 345 (sensitivity: 82.3%, specificity: 100%).

Conclusion

The AI values were predictive of the acute conduction block of SVCI. With AI values of 345 and 379, respectively, conduction block was achieved in the lateral walls at a lower level than in the non-lateral walls.

Catheter ablation and thoracoscopic ablation in long persistent atrial fibrillation with large left atrium

Background

Pulmonary vein antrum isolation (PVAI) is the cornerstone of atrial fibrillation (AF) ablation, but the clinical outcomes of PVAI are unsatisfactory in patients with persistent AF and a large left atrium (LA).

Objectives

We investigated the clinical outcomes following radiofrequency ablation (RFCA), cryoballoon ablation (CBA), and thoracoscopic maze in patients with persistent AF and a large LA.

Methods

We included patients with consecutive persistent AF who had a large LA (LA diameter >50 mm) and underwent RFCA, CBA, or thoracoscopic maze surgery. In the RFCA group, additional linear ablation was performed at the physician’s discretion. The endpoint was 12 months without recurrence of an atrial arrhythmia, including AF, atrial flutter, and atrial tachycardia, following a 90-day blanking period.

Results

We recruited 89 persistent AF patients with a large LA who underwent RFCA (n = 32), CBA (n = 38), or the thoracoscopic maze procedure (n = 19). During the 12-month follow-up, 48 (53.9%) cases of AF recurrence were observed. There was no prognostic difference between groups (50.0% in RFCA vs. 52.6% in CBA vs. 63.2% in thoracoscopic maze, all P > 0.05). Early recurrence during the blanking period was a significant predictor of late recurrence for RFCA and CBA, but not for the thoracoscopic maze.

Conclusion

In persistent AF patients with a large LA, we did not find a prognostic difference RFCA, CBA, or a thoracoscopic maze procedure in recurrence of atrial arrhythmia. Early recurrence predicted late recurrence in catheter ablation, but not in thoracoscopic maze.

Comparison between High-Power Short-Duration and Conventional Ablation Strategy in Atrial Fibrillation: An Updated Meta-Analysis

High-power short-duration (HPSD) setting during radiofrequency ablation has become an attempt to improve atrial fibrillation (AF) treatment outcomes. This study ought to compare the efficacy, safety, and effectiveness between HPSD and conventional settings. PubMed, Embase, and Cochrane Library were searched. Studies that compared HPSD and conventional radiofrequency ablation settings in AF patients were included while studies performed additional ablations on nonpulmonary vein targets without clear recording were excluded. Data were pooled with random-effect model. Efficacy endpoints include first-pass pulmonary vein isolation (PVI), acute pulmonary vein (PV) reconnection, free from AF, and free from atrial tachycardia (AT) during follow-up. Safety endpoints include esophagus injury rate and major complication rate. Effectiveness endpoints include complete PVI rate, total procedure time, PVI time, and PVI radiofrequency ablation (PVI RF) time. We included 22 studies with 3867 atrial fibrillation patients in total (2393 patients received HPSD radiofrequency ablation). Perioperatively, the HPSD group showed a higher first-pass PVI rate (risk ratio, $\text{RR}=1.10$ , $P=0.0001$ ) and less acute PV reconnection rate ( $\text{RR}=0.56$ , $P=0.0004$ ) than the conventional group. During follow-up, free from AF ( $\text{RR}=1.11$ , $P=0.16$ ) or AT ( $\text{RR}=1.06$ , $P=0.24$ ) rate did not differ between HPSD and conventional groups 6-month postsurgery. However, the HPSD group showed both higher free from AF ( $\text{RR}=1.17$ , $P=0.0003$ ) and AT ( $\text{RR}=1.11$ , $P<0.0001$ ) rate than the conventional group 12-month postsurgery. The esophagus injury ( $\text{RR}=0.99$ , $P=0.98$ ) and major complications ( $\text{RR}=0.76$ , $P=0.70$ ) rates did not differ between the two groups. The HPSD group took shorter total procedure time ( $\text{MD}=-33.71$ 95% CI: -43.10 to -24.33, $P<0.00001$ ), PVI time ( $\text{MD}=-21.60$ 95% CI: -25.00 to -18.21, $P<0.00001$ ), and PVI RF time ( $\text{MD}=-13.72$ , 95% CI: -14.45 to -13.00, $P<0.00001$ ) than conventional groups while complete procedure rate did not differ between two groups ( $\text{RR}=1.00$ , $P=0.93$ ). HPSD setting during AF radiofrequency ablation has better effectiveness, efficacy, and similar safety compared with the conventional setting.

Clinical outcomes in patients with persistent atrial fibrillation after technologic advances including contact force-guided and ablation index-guided ablation

Purpose

We aimed to evaluate the influence of technological advances on ablation outcomes in patients with persistent atrial fibrillation (AF) (PeAF). Radiofrequency ablation for patients with AF has advanced, including contact force (CF)-sensing catheters and the ablation index (AI).

Methods

Between 2009 and 2018, we analyzed 173 patients with PeAF who underwent catheter ablation. We categorized them into three groups: AF ablation without CF and AI information (no-CF group, n = 63), with CF without AI (CF-only group, n = 49), and with optimal AI-guided ablation (AI group, n = 61). Early (within 3 months, ER) and late (from 3 months to 1 year, LR) AF recurrence after ablation was assessed. Procedure-related complications were also evaluated.

Results

The baseline characteristics were similar among the 3 groups, excluding the baseline antiarrhythmic drug history. Additional substrate modification after pulmonary vein isolation was significantly low in frequency in the AI group (71.4%, no-CF; 69.4%, CF-only; 41.0%, AI, p = 0.001). The AI group had a shorter mean procedure-related time than the other groups. Both ER and LR of PeAF showed a trend of reduction with technological advances. With a short experience (less than 1 year), the CF-only group showed more ER and LR than that shown by the AI group. However, with a long experience (more than 1 year), ER and LR occurred similarly in the two groups. Procedure-related complications improved with technological advances.

Conclusion

As ablation technology advanced, favorable clinical outcomes with short procedural times were observed. However, prospective, large multicenter studies are needed to verify these results.