Five-year follow-up outcome after catheter ablation of persistent atrial fibrillation using a sequential biatrial linear defragmentation approach: What does atrial fibrillation termination during the procedure imply?

Selective complex fractionated atrial electrogram ablation based on the number-of-fractionation for persistent atrial fibrillation refractory to pulmonary vein isolation

INTRODUCTION

Previous studies have suggested that the prolonged or highly fractionated electrograms during atrial fibrillation (AF) are closely related to the reentrant driver regions. We hypothesized that exploration and ablation of these critical complex atrial fractionated electrograms (CFAE) may improve the outcome of persistent AF (PeAF) refractory to conventional PVI.

METHODS

A total of 73 PeAF patients with residual inducibility or failed cardioversions of AF after PVI were enrolled and underwent number-of-fractionation mapping (NFM) by counting the number of fractionations in 2.5 s at each of the points using the CARTO3 (ICL mode) and EnSite (fractionation map) systems. After NFM, selective CFAE ablation (NFM-CA) targeting the sites of the upper 40% of the counted fraction number (NF40) was performed as an additional procedure for refractory PeAF. We investigated the prognosis of these patients within 24 months after the index ablation procedure and the relationship between changes in activation patterns during the ablation procedure and their prognosis. We also performed a propensity score-matched analysis comparing these patients with historical controls (HC) to identify the optimal indications for NFM-CA.

RESULTS

The AF/AT free survival rate was 79.1% at 12 months and 56.7% at 24 months. Patients with AF termination or AF cycle length prolongation > 21 ms during the procedure had significantly better AF/AT-free survival rates than those without notable activation changes (87.7% vs. 69.0%, logrank p = 0.028). After propensity-matched analysis, AF/AT-free survival showed comparable results between the two groups (1 year; NFM 72.1% vs. HC 77.1%, logrank p = 0.649).

CONCLUSIONS

NFM-CA is a versatile and less invasive adjunctive procedure for patients with PVI-refractory PeAF who showed a comparable prognosis to patients with PVI-compliant PeAF. In particular, remarkable activation changes during the procedure (AFCL prolongation > 21 ms or acute termination) suggest a favorable prognosis.

Concurrent vs Staged Hybrid Ablation for Long-Standing Persistent Atrial Fibrillation: A Propensity-Matched Cohort Study

BACKGROUND

Long-term success rates of catheter ablation (CA) for long-standing persistent atrial fibrillation (LSPAF) are less than satisfactory. Further improvement of ablation methods is crucial for enhancing the treatment of LSPAF.

OBJECTIVES

This study sought to compare the outcomes of concurrent vs staged minimally invasive surgical-catheter hybrid ablation for LSPAF.

METHODS

From December 2015 to December 2021, 104 matched patients (concurrent and staged, 1:1) were included in study. In the concurrent group, both left unilateral thoracoscopic epicardial ablation (EA) and CA were performed simultaneously in one procedure. In the staged group, EA was performed at the first hospitalization. If the patients experienced atrial fibrillation (AF) recurrence, CA was performed between 3 months and 1 year after EA.

RESULTS

In the concurrent group, 4 patients were restored to sinus rhythm after EA, and 41 were patients restored to sinus rhythm during CA; 86.5% (45 of 52) achieved intraprocedural AF termination during concurrent hybrid ablation. In the staged group, all 52 patients underwent staged CA because of the recurrence of AF or atrial tachycardia (AT). Forty-seven (90.4%) patients achieved intraprocedural AF or AT termination during CA. Freedom from AF or AT off antiarrhythmic drugs at 2 years after hybrid ablation was 79.9% ± 5.7% in the concurrent group and 86.0% ± 4.9% in the staged group (P = 0.390). Failure of intraprocedural AF termination (HR: 14.378) was an independent risk factor for AF recurrence after hybrid ablation.

CONCLUSIONS

Both concurrent and staged hybrid ablation could be safely and effectively applied to treat LSPAF. Improving the intraprocedural AF termination rate predicted better outcomes.

Feasibility of catheter ablation in patients with persistent atrial fibrillation guided by fragmented late-gadolinium enhancement areas

BACKGROUND

A computer simulation model has demonstrated that atrial fibrillation (AF) driver can be attached to heterogeneous fibrosis assessed by late gadolinium enhancement magnetic resonance imaging (LGE-MRI). However, it has not been well elucidated in patients with persistent AF. The aim of this study was to investigate whether radiofrequency (RF) applications in the fragmented LGE area (FLA) could terminate AF or convert it to atrial tachycardia (AT) and improve the rhythm outcome.

METHODS

A total of 31 consecutive persistent AF patients with FLAs were enrolled (FLA ablation group, mean age: 69 ± 8 years, mean left atrial diameter: 42 ± 6 mm). A favorable response was defined as direct AF termination or AT conversion during RF applications at the FLA. The rhythm outcome was compared between the FLA ablation group and FLA burden-matched pulmonary vein isolation (PVI) group.

RESULTS

Favorable responses were found in 15 (48%) of 31 patients in the FLA group (AF termination in seven, AT conversion in eight patients), but not in the PVI group. AF recurrence at 12 months follow-up was significantly less in the FLA ablation group than in the PVI group (4 [13%] vs. 12 [39%] of 31 patients, log-rank p = .023). In patients with a favorable response, AT recurred in 1 (7%) of 15 patients, but AF did not.

CONCLUSIONS

FLA ablation could terminate AF or convert it to AT in half of the patients. No AF recurrence was documented in patients with a favorable response.

Substrate Targeted Ablation of Atrial Fibrillation Guided by High Density Voltage Mapping: Long-Term Results

Background

Long-term ablation results for atrial fibrillation (AF) have been disappointing, particularly for non-paroxysmal AF (NPAF). We hypothesize fibrosis in paroxysmal AF (PAF) and NPAF would be reflected in voltage fragmentation and visualized by high density mapping. Targeted ablation of discrete low voltage bridges (LVB) would eliminate endocardial fragmentation and should have a positive effect on long-term sinus rhythm (SR) survival.

Objective

To assess the efficacy of LVB ablation on SR survival in patients with PAF and NPAF, as well as, determine its impact on P wave duration (PWD) and LA volume (LAV).

Methods

56 patients (29PAF/26NPAF) had a voltage gradient map (VGM) created, high and low voltage limits were adjusted to image LVB. Ablation was performed until no LVB were observed. Baseline PWD and LAV were obtained and reassessed 6 months' post ablation. Patients were followed for 5 years with intermittent monitors.

Results

Termination of AF in NPAF was 88%. PWD normalized in PAF and were normal in NPAF post ablation. LAV decreased significantly in NPAF. At 5 years, SR was observed in 89% of PAF and 67% of NPAF.

Conclusions

1. LVB ablation terminates AF in NPAF 88%; 2. Both PWD and LAV were improved; 3. Maintenance of SR was observed in 89% and 67% (PAF vs NPAF); 4. The present study demonstrates efficacy of a simplified, individualized, and unified methodology for AF ablation.

Relationship between Atrial Tissue Remodeling and ECG Features in Atrial Fibrillation

The difference in the atrial organizational structure between patients with atrial fibrillation (AF) and those with sinus rhythm was investigated. In order to analyze the rationality in explaining the electrocardiogram (ECG) characteristics of AF with statistics data or tissue remodeling model, and the logical relationship between the hypothesis of pulmonary veins (PV) muscle sleeves and that of multi wavelets in mechanism of AF, we examined the expression of collagen volume fraction of type I (CVF-I) with picrosirius red staining, connexin 40 (Cx40) by immunohistochemistry, and intercalated disc (ID) using transmission electron microscope in atrial tissue. The results showed that there was significant difference in the expression of CVF-I (t=3.827, P<0.01), Cx40 (t=4.21, P<0.01), and groups of the ID that keeping the electrical transmission and atrial electrical coupling synchronization (t=15.116, P<0.001), but no significant difference was found in total IDs (t=0.611, P=0.543) between patients with AF and those with sinus rhythm. The quantitative differences in the tissue remodeling could not explain the ECG characteristics of AF. The number of normal IDs and abnormal distribution are the structural basis to trigger and maintain atrial electrical remodeling, and induce and maintain AF. Such histological reconstruction supports the hypothesis of multi wavelets and can also explain ECG features.

Catheter ablation of paroxysmal atrial fibrillation in patients with sick sinus syndrome

Sick sinus syndrome (SSS) frequently coexists with atrial fibrillation (AF). The results of AF ablation in patients with SSS have not been fully evaluated. We retrospectively investigated 65 patients with paroxysmal AF (PAF) and SSS who underwent AF ablation using either radiofrequency (n = 50) or cryoballoon ablation (n = 15) in our institute. Forty-nine (75.4%) patients had a median of 5.6 (4.8-6.0) s of documented sinus pauses prior to the procedure (42 patients on antiarrhythmic drugs), and were observed when AF terminated in 47 patients. Successful pulmonary vein isolation was achieved in all, and substrate modification was added in 3 patients. Freedom from recurrent atrial arrhythmias after single procedures was 58.7, 45.2, and 38.9% at 1, 2, and 3 years after the initial procedure. During a 23.4 (11.1-40.7) month median follow-up and after 1.4 ± 0.6 sessions, 80.6% of patients were free from arrhythmia recurrence; however, permanent pacemaker implantations were required in 9 (13.8%) patients at a median of 5.3 (2.9-21.0) months after initial procedures. The average heart rate did not significantly differ before or a median of 2.5 (1.2-5.3) months post-procedure (76.7 ± 17.4 vs. 73.5 ± 14.6 bpm, p = 0.90). Multivariate analyses revealed that larger left atrial diameters [odds ratio (OR) 1.21, 95% confidential interval (CI) 1.01-1.45, p = 0.042] were independent predictor of AF recurrence, and SSS type 1 was the sole predictor of pacemaker implantations (OR 10.30, 95% CI 1.38-76.7, p = 0.023), respectively. AF ablation obviated permanent pacemaker implantations in the majority of the patients with SSS and PAF, and SSS type 1 was a sole factor predicting pacemaker implantations.

Impact of catheter ablation of atrial fibrillation on long-term clinical outcomes in patients with heart failure

BACKGROUND

Heart failure (HF) promotes atrial fibrillation (AF) and AF worsens HF. This study aimed to investigate the long-term clinical outcomes after AF ablation in patients with HF.

METHODS AND RESULTS

A total of 106 consecutive HF patients, including 51 (48.1%) with a reduced left ventricular ejection fraction (LVEF) (HFrEF) and 55 (51.9%) with a preserved LVEF (HFpEF), underwent AF ablation. All patients underwent successful pulmonary vein antrum isolation, and substrate modification was added in 38 (35.8%). The mean follow-up period was 32.4±18.6 months, and mean number of procedures was 1.4±0.5 per patient. Low-dose antiarrhythmic drugs were combined in 29 (27.3%) patients. Freedom from recurrent atrial arrhythmias (ATa), HF-related hospitalizations, and the composite endpoint (all-cause death, stroke, HF-related hospitalizations) at 3 years was 88.7%, 97.6%, and 97.6% in HFrEF patients, and 79.3%, 96.2%, and 91.8% in HFpEF patients, respectively. LVEF normalization (≥50%) was observed in 37 (72.5%) HFrEF patients post-ablation, and a smaller LV diastolic diameter (LVDd) was the sole predictor [odds ratio (OR)=0.863; 95% confidence interval (CI)=0.779-0.955, p=0.005]. Shortening of the LVDd (≥5mm) was observed in 16 (29.1%) HFpEF patients post-ablation, and no recurrence after the initial procedure was the sole predictor (OR=6.229; 95% CI=1.524-25.469, p=0.011).

CONCLUSIONS

Catheter ablation of AF could be one of the important therapeutic options in the management of patients with HF combined with AF regardless of the type of HF.

Beyond Pulmonary Vein Isolation: the Role of Additional Sites in Catheter Ablation of Atrial Fibrillation

PURPOSE OF REVIEW

Pulmonary vein (PV) isolation is the cornerstone of atrial fibrillation (AF) ablation. However, the long-term procedural outcome remains suboptimal and there is a frequent need for repeat ablation procedure, especially in patients with non-paroxysmal AF. The review article summarizes the rationales, recent evidences, and strategies of ablation of extra-PV sites and its clinical outcomes.

RECENT FINDINGS

It is a consensus that durable PV isolations are a definite therapy in patients with paroxysmal AF. In non-paroxysmal AF, many laboratories still believe that adequate substrate ablation outside PVs is definitely required. Empirical linear ablation is not recommended because of difficulty in achieving complete linear block, unless macro-reentry atrial tachycardia developed during procedure. Most of laboratories applied complex fractionated atrial electrogram (CFAE) ablation after PV isolation in non-paroxysmal AF, but the efficacy is limited in the long-term follow-up studies. A combined approach using CFAE, non-linear similarity, and phase mapping strategy to identify rotors or focal sources for substrate modification increases the ablation outcome, when compared to CFAE ablation alone. Provocative test with mapping of non-PV triggers is also recommended in all patients to improve long-term ablation success. Ablation beyond PV isolation is important, especially in non-paroxysmal AF patients, to modify the diseased atrial substrate and eliminate the non-PV triggers, which in turn improve the ablation outcome.