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.

Prognostic value of heart rate variability in atrial fibrillation recurrence following catheter ablation: A systematic review and meta-analysis

Background

Atrial fibrillation (AF) has been a worldwide health issue with increasing prevalence and mortality. Recently, increasing attention has been gained to the relationship between heart rate variability (HRV) and the clinical prognosis of AF catheter ablation. We aimed to evaluate the prognostic value of HRV in AF recurrence.

Methods

We systematically searched Web of Science, PubMed, and Embase from inception until 17 August 2022 to conduct the systematic review and meta-analysis. We included the studies reporting the predictive value of HRV parameters for AF recurrence or in which HRV parameters in AF recurrence and non-recurrence groups were individually reported.

Results

Finally, we enrolled 16 studies, including 2,352 patients. Higher rMSSD could independently predict AF recurrence following catheter ablation (OR: 1.02, 95% CI: 1.00-1.04; p = 0.03). Higher HF (OR: 1.55, 95% CI: 1.05-2.28; p = 0.03) and lower LF/HF (OR: 1.12, 95% CI: 1.03-1.20; p = 0.004) could independently predict AF recurrence within 1 year. Higher SDNN (OR: 1.02, 95% CI: 101-1.02; p = 0.0006) could independently predict AF recurrence among patients with paroxysmal AF. Almost all HRV parameters within 3 days after catheter ablation and lnHF, lnLF, and rMSSD at 3 months after catheter ablation performed significant differences in AF recurrence and non-recurrence groups.

Conclusion

Heart rate variability, especially higher rMSSD (within short-term and long-term periods), was closely related to recurrent AF following catheter ablation, highlighting the clinical importance of HRV in the prognosis of AF following catheter ablation.

The effect of posterior wall isolation for persistent atrial fibrillation on recurrent arrhythmia

INTRODUCTION

It is important to consider recurrent arrhythmia after catheter ablation for persistent atrial fibrillation (AF) for planning an ablation strategy. However, the studies are limited to pulmonary vein isolation (PVI) plus posterior wall isolation (PWI), which were reported to improve procedural outcomes. The objective of this study is to evaluate the effect of PWI on recurrent arrhythmia.

METHODS

This is an observational study on patients with persistent AF comparing PVI plus PWI and PVI only strategies. In PVI plus PWI group, linear ablation of the left atrium roofline and bottom line were performed to achieve PWI after PVI. Some patients with AF recurrence underwent the second procedure. The presence of recurrent arrhythmia and results of the second procedures were evaluated.

RESULTS

A total of 181 patients (mean age, 66.9 ± 10.2 years; male, 76.8%) were included. PVI plus PWI group and PVI only group consisted of 90 and 91 patients, respectively. AF recurrence was observed in 28 of 90 (31.1%) patients with PVI plus PWI and in 43 of 91 (47.3%) with PVI only, and log-rank test did not show any significant difference (p = .35). The occurrence of recurrent persistent AF was significantly lower in PVI plus PWI group than in PVI only group (5/90; 5.6% vs. 18/91; 20.9%, p = .002). There was no significant difference between the two groups in recurrent paroxysmal AF and atrial tachycardia (AT).

CONCLUSION

PWI, in addition to PVI, for persistent AF was significantly related to fewer episodes of recurrent persistent AF, and it did not increase recurrent AT.

Catheter Ablation in the Treatment of Atrial Fibrillation

Catheter ablation (CA) of the pulmonary veins for atrial fibrillation (AF) is growing exponentially and is the most commonly performed electrophysiologic procedure. Initial descriptions focused on CA for paroxysmal AF, and now more recently expanded in application to persistent AF and those with comorbid heart failure. Efforts to improve success have and continue to address issues such as pulmonary vein "reconnection" following ablation through different ablative energy modalities, and the use of a "hybrid" surgical/endocardial combined approach in persistent forms of AF. Technologic advances as well are concurrently seeking to improve safety, particularly regarding the incidence of atrio-esophageal fistula in this seemingly ever-growing ablation population.

Left atrial posterior wall isolation affects complex fractionated atrial electrograms in persistent atrial fibrillation

BACKGROUND

The impact of left atrial posterior wall isolation (LAPWI) on the complex fractionated atrial electrogram (CFAE) is unknown.

METHODS

CFAE mapping was performed before and after LAPWI in 46 patients with persistent atrial fibrillation (AF).

RESULTS

LAPWI decreased both the variable (fractionated index ≤ 120 ms; from 60 ± 4 cm2 to 50 ± 4 cm2, P < 0.001) and continuous (fractionated index ≤ 50 ms; from 4.2 ± 1.0 cm2 to 3.5 ± 0.9 cm2, P = 0.036) CFAE areas. Especially, the CFAE areas on the bottom and roof walls of the left atrium and on the posterior and bottom walls of the right atrium significantly decreased after LAPWI. The distribution of variable CFAE areas was not different between the AF-recurrence (n = 9) and AF-free (n = 37) groups before LAPWI; however, it was larger in the anterior and septal walls of the right atrium in the AF-recurrence group than in the AF-free group after LAPWI (anterior wall, 8% ± 2% vs 5% ± 1%, P = 0.048; septal wall, 23% ± 4% vs 16% ± 1%, P = 0.043). The distribution of continuous CFAE areas on the bottom wall of the right atrium was larger in the AF-recurrence group than in the AF-free group both before LAPWI (30% ± 20% vs 4% ± 2%, P = 0.008) and after LAPWI (25% ± 25% vs 3% ± 1%, P = 0.027).

CONCLUSIONS

LAPWI decreased the CFAE areas and affected their distribution, which contributed to AF recurrence.

Heart rate variability after radiofrequency ablation of epicardial ganglionated plexuses on the ovine left atrium

Background

Ganglionated plexuses (GP) are terminal parts of cardiac autonomous nervous system (ANS). Radiofrequency ablation (RFA) for atrial fibrillation (AF) possibly affects GP. Changes in heart rate variability (HRV) after RFA can reflect ANS modulation.

Methods

Epicardial RFA of GP on the left atrium (LA) was performed under the general anesthesia in 15 mature Romanov sheep. HRV was used to assess the alterations in autonomic regulation of the heart. A 24 − hour ECG monitoring was performed before the ablation, 2 days after it and at each of the 12 following months. Ablation sites were evaluated histologically.

Results

There was an instant change in HRV parameters after the ablation. A standard deviation of all intervals between normal QRS (SDNN), a square root of the mean of the squared differences between successive normal QRS intervals (RMSSD) along with HRV triangular index (TI), low frequency (LF) power and high frequency (HF) power decreased, while LF/HF ratio increased. Both the SDNN, LF power and the HF power changes persisted throughout the 12 − month follow − up. Significant decrease in RMSSD persisted only for 3 months, HRV TI for 6 months and increase in LF/HF ratio for 7 months of the follow − up. Afterwards these three parameters were not different from the preprocedural values.

Conclusions

Epicardial RFA of GP’s on the ovine left atrium has lasting effect on the main HRV parameters (SDNN, HF power and LF power). The normalization of RMSSD, HRV TI and LF/HF suggests that HRV after epicardial RFA of GPs on the left atrium might restore over time.

Complete Isolation of the Left Atrial Posterior Wall (Box Lesion) to Treat Longstanding Persistent Atrial Fibrillation

INTRODUCTION

The left atrial posterior wall has been shown to play na important role in AF pathophysiology.

OBJECTIVE

Evaluate the efficacy of an ablation strategy designed to completely isolate the LA posterior wall, on top of PV isolation. Methods and Results: 25 pts (72% male age 65 ± 12 years) undergoing AF ablation for persistent or long term persistent AF. Mean AF duration was 11 ± 3 months and mean LA diameter was 4.8 ± 0.4 mm. After complete PVI, a "Roof Line" was created between the top of each contralateral set of lesions and a "floor line" closed the posterior wall in a "Box" fashion, connecting the bottom of each set of contralateral lesions. After an average follow-up of 16 ± 2 months, 20 patients (80%) were free of any atrial arrhythmia recurrences (18 of whom off drugs). Five patients (20%) had sustained atypical flutter and required a new ablation procedure. All these patients had mitral isthmus dependent flutters and no electrical conduction in the PVs or posterior wall were detected.

CONCLUSIONS

Complete LA posterior wall isolation on top of PV is associated with good outcomes in patients with persistent and long-standing persistent AF when performed using meticulous bidirectional isolation criteria and adenosine infusion. Recurrences occur predominately as perimitral flutter, without gaps in the posterior wall.

Denervation as a common mechanism underlying different pulmonary vein isolation strategies for paroxysmal atrial fibrillation: evidenced by heart rate variability after ablation

BACKGROUNDS

Segmental and circumferential pulmonary vein isolations (SPVI and CPVI) have been demonstrated to be effective therapies for paroxysmal atrial fibrillation (PAF). PVI is well established as the endpoint of different ablation techniques, whereas it may not completely account for the long-term success.

METHODS

181 drug-refractory symptomatic PAF patients were referred for segmental or circumferential PVI (SPVI = 67; CPVI = 114). Heart rate variability (HRV) was assessed before and after the final ablation.

RESULTS

After following up for 62.23 ± 12.75 months, patients underwent 1.41 ± 0.68 procedures in average, and the success rates in SPVI and CPVI groups were comparable. 119 patients were free from AF recurrence (SPVI-S, n = 43; CPVI-S, n = 76). 56 patients had recurrent episodes (SPVI-R, n = 21; CPVI-R, n = 35). Either ablation technique decreased HRV significantly. Postablation SDNN and rMSSD were significantly lower in SPVI-S and CPVI-S subgroups than in SPVI-R and CPVI-R subgroups (SPVI-S versus SPVI-R: SDNN 91.8 ± 32.6 versus 111.5 ± 36.2 ms, rMSSD 47.4 ± 32.3 versus 55.2 ± 35.2 ms; CPVI-S versus CPVI-R: SDNN 83.0 ± 35.6 versus 101.0 ± 40.7 ms, rMSSD 41.1 ± 22.9 versus 59.2 ± 44.8 ms; all P < 0.05). Attenuation of SDNN and rMSSD remained for 12 months in SPVI-S and CPVI-S subgroups, whereas it recovered earlier in SPVI-R and CPVI-R subgroups. Multivariate logistic regression analysis identified SDNN as the only predictor of long-term success.

CONCLUSIONS

Beyond PVI, denervation may be a common mechanism underlying different ablation strategies for PAF.

Efficacy of cut-and-sew box isolation of the posterior left atrium for treatment of atrial fibrillation-long-term follow-up after a modified maze procedure

BACKGROUND

Box isolation of the posterior left atrium is one surgical or catheter ablative approach for treating atrial fibrillation (AF). In such cases, incomplete transmurality or recovery of pulmonary vein conduction after the application of various ablative techniques is considered the main reason for the recurrence of postprocedural arrhythmia. The use of solely cut-and-sew box isolation does not have these disadvantages and therefore demonstrates maximum efficacy for this therapeutic approach.

METHODS

We treated 15 patients with both an indication for open heart surgery and AF (2 paroxysmal, 6 short persistent [<12 months], and 7 long persistent [>12 months] cases) with a solely cut-and-sew box lesion. These patients were then retrospectively followed up over the long term with respect to the end point of freedom of atrial tachyarrhythmias >30 seconds.

RESULTS

The median follow-up duration was 42 months (range, 32-84 months). Five (63%) of 8 patients with preoperative paroxysmal or short persistent AF had no arrhythmia recurrence, whereas arrhythmia recurrence was documented in all 7 patients with preoperative long persistent AF.

CONCLUSIONS

Despite reliable transmural isolation with cut-and-sew lesions, we observed long-term arrhythmia recurrence in patients who had preoperative paroxysmal or short persistent AF, suggesting that therapy approaches that are more complex than box isolation might be needed for selected patients to achieve long-term stable sinus rhythm, despite the initially paroxysmal or short persistent character of the arrhythmia. A high rate of recurrence in patients with severe structural heart disease and preoperative long persistent AF might indicate that, in general, isolation of the left posterior atrium alone is not an adequate therapeutic approach for these patients.