Comparison between linear and focal ablation of complex fractionated atrial electrograms in patients with non-paroxysmal atrial fibrillation: a prospective randomized trial

Sex-Related Differences in Left Atrial Low-Voltage Areas According to CHA2DS2-VA Scores among Patients with Atrial Fibrillation

(1) Background: We hypothesized that female sex would have a differential impact on left atrial (LA) low-voltage areas (LVAs) according to CHA2DS2-VA scores. (2) Methods: This study included 553 patients who underwent radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF). LVAs were defined as regions with bipolar peak-to-peak voltages of <0.5 mV. The proportion of LVAs was calculated by dividing the total LVA by the LA surface area. (3) Results: There was no sex-related difference in LA LVAs among patients with a CHA2DS2-VA scores ≤ 2. The proportion of LVAs was significantly higher in females among patients with CHA2DS2-VA scores of 3 or 4 (10.1 (4.7−15.1)% vs. 15.8 (9.2−32.1)%; p = 0.027). Female sex was significantly associated with extensive LVAs (LVA proportion ≥ 30%). Females had odd ratios of 27.82 (95% confidence interval (CI) 3.33−756.8, p = 0.01), and 1.53 (95% CI 0.81−2.83, p = 0.184) for extensive LAVs in patients with CHA2DS2-VA scores ≥ 3 and CHA2DS2-VA scores < 3, respectively. In the multiple regression model, female patients with a CHA2DS2-VA ≥3 were significantly associated with a higher proportion of LVAs (β = 8.52, p = 0.039). (4) Conclusions: Female sex was significantly associated with extensive LVAs, particularly when their CHA2DS2-VA scores were ≥3. This result suggests that female sex has a differential effect on the extent of LVAs based on the presence of additional risk factors.

Combined epicardial and endocardial approach for redo radiofrequency catheter ablation in patients with persistent atrial fibrillation: a randomized clinical trial

AIMS

An epicardial approach is an effective means to detect and eliminate residual potentials in non-transmural lesions created during prior endocardial ablation. We sought to determine the impact of a combined epicardial and endocardial approach compared with a conventional endocardial approach, on recurrence-free survival after redo ablation.

METHODS AND RESULTS

Participants with recurred persistent atrial fibrillation after prior endocardial ablation were randomized (1:1) to undergo treatment with the combined approach (epicardial followed by endocardial ablation) for the treatment group or conventional approach (endocardial ablation only) for the control group. The primary outcome was the time to recurrence of atrial fibrillation or atrial tachycardia following a 90-day blanking period within 12 months after the procedure. The secondary safety outcome was the occurrence of procedure-related complications within 24 h after the procedure. Of 100 randomized participants {median age, 59.0 [(interquartile range (IQR): 53.8-64.3] years, including 16% women, with one prior ablation (IQR: 1-1)}, 93 (93%) completed the trial. Events relevant to the primary outcome occurred in 16 patients in the treatment group and in 21 patients in the control group {Kaplan-Meier estimator percentages, 32 vs. 42%; hazard ratio, 0.71 [95% confidence interval (CI): 0.37-1.37]}. The periprocedural complication rate was lower in the treatment group [2 vs. 16%; odds ratio, 0.11 (95% CI: 0.00-0.87)] with similar achievement of the procedural endpoint in the two groups.

CONCLUSION

In the redo procedure for persistent atrial fibrillation, the combined approach had no significant difference of recurrence-free survival and a lower procedural complication rate compared with the conventional approach.

Comparing efficacy and safety in catheter ablation strategies for atrial fibrillation: a network meta-analysis

BACKGROUND

There is no consensus on the most efficient catheter ablation (CA) strategy for patients with atrial fibrillation (AF). The objective of this study was to compare the efficacy and safety of different CA strategies for AF ablation through network meta-analysis (NMA).

METHODS

A systematic search of PubMed, Web of Science, and CENTRAL was performed up to October 5th, 2020. Randomized controlled trials (RCT) comparing different CA approaches were included. Efficacy was defined as arrhythmia recurrence after CA and safety as any reported complication related to the procedure during a minimum follow-up time of 6 months.

RESULTS

In total, 67 RCTs (n = 9871) comparing 19 different CA strategies were included. The risk of recurrence was significantly decreased compared to pulmonary vein isolation (PVI) alone for PVI with renal denervation (RR: 0.60, CI: 0.38-0.94), PVI with ganglia-plexi ablation (RR: 0.62, CI: 0.41-0.94), PVI with additional ablation lines (RR: 0.8, CI: 0.68-0.95) and PVI in combination with bi-atrial modification (RR: 0.32, CI: 0.11-0.88). Strategies including PVI appeared superior to non-PVI strategies such as electrogram-based approaches. No significant differences in safety were observed.

CONCLUSIONS

This NMA showed that PVI in combination with additional CA strategies, such as autonomic modulation and additional lines, seem to increase the efficacy of PVI alone. These strategies can be considered in treating patients with AF, since, additionally, no differences in safety were observed. This study provides decision-makers with comprehensive and comparative evidence about the efficacy and safety of different CA strategies.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registry number: CRD42020169494 .

Diversity and complexity of the cavotricuspid isthmus in rabbits: A novel scheme for classification and geometrical transformation of anatomical structures

The aim of this study was to describe the morphology of the cavotricuspid isthmus (CTI) in detail and introduce a comprehensive scheme to describe the topology of this region based on functional considerations. This may lead to a better understanding of isthmus-dependent flutter and fibrillation and to improved intervention strategies. We used images of the cavotricuspid isthmus from 52 rabbits of both sexes with a median weight of 3.40 ± 0.93 kg. The area of the CTI was 124.25 ± 42.14 mm² with 53.28 ± 21.13 mm² covered by pectinate muscles connecting the terminal crest and the vestibule. Isthmus length decreased from inferolateral (13.09 ±2.14 mm) to central (9.85 ± 2.14 mm) to paraseptal (4.88 ± 1.96 mm) resembling the overall human geometry. Ramification sites of pectinate muscles were identified and six levels dividing the CTI from posterior to anterior were introduced. This allowed the classification of pectinate muscle segments based on the connected ramification level. To account for the high inter-individual variations in size and shape, the CTI was projected onto a normalized reference frame using bilinear transformation. Furthermore, two measures of complexity were introduced: (i) the ramification index, which reflects the total number of muscle segments connected to a ramification site and (ii) the complexity index, which reflects the type of ramification (branching or merging site). Topological analysis showed that the complexity of the pectinate muscle network decreases from inferolateral to paraseptal and that the number of electrically uncoupled parallel pathways increases in the central section between the terminal crest and the vestibule which introduces potential reentry pathways.

Ablation of persistent atrial fibrillation based on high density voltage mapping and complex fractionated atrial electrograms: A randomized controlled trial

INTRODUCTION

Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) catheter ablation. However, a PVI alone has been considered insufficient for persistent AF. This study aimed to evaluate the efficacy of persistent AF ablation targeting complex fractionated atrial electrogram (CFAE) areas within low voltage zones identified by high-resolution mapping in addition to the PVI.

METHODS

We randomized 50 patients (mean age 58.4 ± 9.5 years old, 86.0% males) with persistent AF to a PVI + CFAE group and PVI only group in a 1:1 ratio. CFAE and voltage mapping was performed simultaneously using a Pentaray Catheter with the CARTO3 CONFIDENSE module (Biosense Webster, CA, USA). The PVI + CFAE group, in addition to the PVI, underwent ablation targeting low voltage areas (<0.5 mV during AF) containing CFAEs.

RESULTS

The mean persistent AF duration was 24.0 ± 23.1 months and mean left atrial dimension 4.9 ± 0.5 cm. In the PVI + CFAE group, AF converted to atrial tachycardia (AT) or sinus rhythm in 15 patients (60%) during the procedure. The PVI + CFAE group had a higher 1-year AF free survival (84.0% PVI + CFAE vs 44.0 PVI only, P = .006) without antiarrhythmic drugs. However, there was no difference in the AF/AT free survival (60.0% PVI + CFAE vs 40.0% PVI only, P = .329).

CONCLUSION

Persistent AF ablation targeting CFAE areas within low voltage zones using high-density voltage mapping had a higher AF free survival than a PVI only. Although recurrence with AT was frequent in the PVI+CFAE group, the sinus rhythm maintenance rate after redo procedures was 76%.

Incremental predictive value of left atrial strain and left atrial appendage function in rhythm outcome of non-valvular atrial fibrillation patients after catheter ablation

Objective

The purpose of this study was to develop a non-invasive and convenient nomogram based on speckle tracking echocardiography, left atrial appendage function and clinical factors to predict the risk of atrial fibrillation (AF) recurrence after catheter ablation.

Methods

A total of 124 prospectively consecutive patients with AF treated with catheter ablation in our hospital was retrospectively analysis. Baseline echocardiographic parameters were measured by using transthoracic and transesophageal echocardiography before ablation. Multivariate analysis was performed for selecting predictors for a nomogram and internal validation and calibration were evaluated by the bootstep method.

Results

During the follow-up of 12±3 months, 41 patients (33.1%) occurred AF recurrence after catheter ablation, while 83 patients (66.9%) had maintained sinus rhythm. Four predictors (AF type, left atrial appendage emptying flow velocity, left Atrial maximal volumes index and global longitudinal strain) with the P<0.5 was selected into the nomogram according to multivariate findings. Internal validation by bootstrapping with 1000 resamples was determined C-index of the nomogram for prediction AF recurrence was 0.901, which showed optimal discrimination and calibration of the established nomogram.

Conclusions

Nomogram based on echocardiography and clinical characteristics had good predictive performance for the possibility of AF recurrence, which providing practical guidance for individualised management of patients with AF after catheter ablation.

A novel predictive model for late recurrence after catheter ablation for atrial fibrillation using left appendage volume measured by cardiac computed tomography

Larger left atrial appendage (LAA) volume is associated with a higher risk of late recurrence (LR) in patients undergoing radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF). However, it is unclear whether LAA volume predicts LR, independent of established risk factors. We sought to evaluate the value of LAA volume in predicting LR after RFCA for AF and to develop a score prediction model including LAA volume for these patients. We retrospectively studied 992 patients who underwent RFCA for AF and cardiac computed tomography before RFCA at a single center. At 3 years after RFCA, 362 patients (36.5 %) experienced recurrence. The multivariate Cox regression model showed that age ≥ 75 years (10 points), non-paroxysmal AF (9 points), diabetes mellitus (4 points), left atrial volume index (1 point per 10 ml/m² rounded to the nearest integer), and the second (4.7 to < 7 ml/m²; 4 points) and third (≥ 7 ml/m²; 5 points) tertiles of the LAA volume index were independent risk factors LR. The above-mentioned risk factors were included in the integrated score model, and the C-index of the proposed score model was 0.715 (95 % confidence interval [CI] 0.679-0.752). LAA volume is an independent predictor of LR and the predictive model including LAA volume showed good discrimination power. These findings provide evidence for the inclusion of LAA volume in the risk stratification for AF recurrence in patients undergoing RFCA for AF.

Individualised Approaches for Catheter Ablation of AF: Patient Selection and Procedural Endpoints

Pulmonary vein isolation (PVI) is the cornerstone of AF ablation, but studies have reported improved efficacy with high rates of repeat procedures. Because of the large interindividual variability in the underlying electrical and anatomical substrate, achieving optimal outcomes requires an individualised approach. This includes optimal candidate selection as well as defined ablation strategies with objective procedure endpoints beyond PVI. Candidate selection is traditionally based on coarse and sometimes arbitrary clinical stratification such as AF type, but finer predictors of treatment efficacy including biomarkers, advanced imaging and electrocardiographic parameters have shown promise. Numerous ancillary ablation strategies beyond PVI have been investigated, but the absence of a clear mechanistic and evidence-based endpoint, unlike in other arrhythmias, has remained a universal limitation. Potential endpoints include functional ones such as AF termination or non-inducibility and substrate-based endpoints such as isolation of low-voltage areas. This review summarises the relevant literature and proposes guidance for clinical practice and future research.