Atrial Tachycardias Following Persistent Atrial Fibrillation Ablation: Predictors of Recurrence After the Repeat Ablation

Focal pulsed field ablation in complex atrial tachycardia: First clinical experience and 1-year outcome

BACKGROUND

Pulsed field ablation (PFA) has become increasingly important in the treatment of cardiac arrhythmias. In addition to single-shot devices mainly used for pulmonary vein isolation, focal PFA may provide a treatment option that increases the versatility of the technique.

OBJECTIVE

The purpose of this study was to provide data on feasibility, safety, and long-term outcome of focal PFA for ablation of complex atrial tachycardia (AT).

METHODS

All consecutive patients (n = 34) with complex AT treated at our department between 2022 and 2023 with a focal PFA system (CENTAURI™, Galvanize Therapeutics) were included. The majority of patients (32/34) previously had undergone at least 1 radiofrequency ablation. Established contact force-sensing catheters were used for PFA application in combination with a PFA generator. Pulsed electric field trains were conducted in a R-wave triggered manner.

RESULTS

Acute procedural success was accomplished in all patients. PFA included creation of 51 linear lesions and (re)isolation of 12 pulmonary veins. Mean procedural duration was 102.7 ± 30.3 minutes, with left atrial dwell time of 75.0 ± 24.7 minutes. Mean fluoroscopy duration was 8.7 ± 5.3 minutes. No complications occurred. After mean follow-up of 340.9 ± 130.1 days, recurrence of any AT occurred in 15 patients (44.1%). During 9 reablations, 3 gaps in previously created linear lesions were detected; the majority of recurrences (n = 6) were not related to previous PFA lesion creation.

CONCLUSION

Focal PFA of complex AT substrates was safe and efficient. Acute procedural success was 100%. After 1 year, the majority of patients were in sinus rhythm. A minority of recurrences was caused by insufficient PFA lesion creation.

Efficacy and feasibility of vein of Marshall ethanol infusion during persistent atrial fibrillation ablation: A systematic review and meta-analysis

BACKGROUND

Catheter ablation (CA) is currently used to treat persistent atrial fibrillation (PeAF). However, its effectiveness is limited. This study aimed to estimate the effectiveness of the vein of Marshall absolute ethanol injection (VOM-EI) for PeAF ablation.

HYPOTHESIS

Adjunctive vein of Marshall ethanol injection (VOM-EI) strategies are more effective than conventional catheter ablation (CA) and have similar safety outcomes.

METHODS

We extensively searched the literature for studies evaluating the effectiveness and safety of VOM-EI + CA compared with CA alone. The primary endpoint was the rate of acute bidirectional block of the isthmus of the mitral annulus (MIBB). The secondary endpoints were atrial fibrillation (AF) or atrial tachycardia (AT) recurrence over 30 seconds after a 3-month blanking period. Weighted pooled risk ratios (RRs) and corresponding 95% confidence intervals (CIs) were calculated using a random effects model.

RESULTS

Based on the selection criteria, nine studies were included in this systematic review, including patients with AF (n = 2508), persistent AF (n = 1829), perimitral flutter (n = 103), and perimitral AT (n = 165). There were 1028 patients in the VOM-EI + CA group and 1605 in the CA alone group. The VOM-EI + CA group showed a lower rate of AF/AT relapse (RR = 0.70; 95% CI = 0.53-0.91; p = .008) and a higher rate of acute MIBB (RR = 1.29; 95% CI = 1.11-1.50; p = .0007) than the CA alone group.

CONCLUSION

Our meta-analysis revealed that adjunctive VOM-EI strategies are more effective than conventional CA and have similar safety outcomes.

Safety and patient-reported outcomes in index ablation versus repeat ablation in atrial fibrillation: insights from the German Ablation Registry

BACKGROUND

Pulmonary vein isolation is an established strategy for catheter ablation of atrial fibrillation (AF). However, in a significant number of patients, a repeat procedure is mandatory due to arrhythmia recurrence. In this study, we report safety data and procedural details of patients undergoing index ablation versus repeat ablation in a registry-based real-life setting.

METHODS

Patients from the German Ablation Registry, a prospective, multicentre registry of patients undergoing ablation between January 2007 and January 2010 were included.

RESULTS

A total of 4155 patients were enrolled in the study. Group I (index ablation) consisted of 3377/4155 (82.1%) and group II (repeat ablation) of 738/4155 (17.9%). Patients in group I had a significantly higher ratio of paroxysmal AF (69.3% vs 61.9%, p < 0.001) and significantly less persistent AF (30.7% vs 38.1%, p < 0.001). The repeat group showed significantly lower mean RF application duration (2580 s. vs 1960, p < 0.001), less fluoroscopy time (29 min. vs. 27 min., p < 0.001), less mean dose area product (DAP) (3744 cGy × cm2 vs 3325 cGy × cm2, p = 0.001), and shorter study duration (181.2 min. vs 163.6 min., p < 0.001). No statistical difference between the groups was found in terms of mortality (0.3% vs 0.1%, p = 0.39), MACE (0.4% vs 0.3%, p = 0.58), MACCE (0.8% vs 0.6%, p = 0.47), composite safety endpoint (1.5% vs 1.4%, p = 0.76), and arrhythmia recurrence (43.8% vs 41.9%, p = 0.37) during 1-year follow-up. Both groups reported to have improved or no symptoms (80.4% vs 77.8%, p = 0.13).

CONCLUSION

Repeat catheter ablation is safe and provides a symptomatic relief comparable to index ablation. Repeat procedures are significantly shorter and use less fluoroscopy.

Retrospective analysis of FIRM-guided ablation in patients with recurrent atrial fibrillation: a single-center study

BACKGROUND

Ablation of recurrent atrial fibrillation (AF) is common. Studies indicate that AF recurrence is primarily due to pulmonary vein (PV) re-conduction. This retrospective analysis characterized and evaluated recurrent AF patients using focal impulse and rotor mapping (FIRM) plus PV re-isolation, with follow up at 3, 6, 12, and 24 months after the repeat ablation.

METHODS AND RESULTS

Patients (consecutive, n = 100) underwent FIRM-guided ablation followed by conventional PV re-isolation for recurrent AF treatment. All FIRM patients had failed one or more conventional ablation procedures (1.4 ± 0.08) for paroxysmal (14%), persistent (15%), and long-standing persistent (71%) AF. Stable rotors were identified in 97/100 patients: 60% in the right atrium (RA) and 82% in left atrium (LA) (mean 1.5 ± 0.8 and 2.1 ± 1.2 per patient, respectively). No correlation was noted between the previous number of ablations, AF duration, or LA diameter to the number of rotors (R² = 0.0039, R² = 0.0017, and R² = 0.006, respectively). In this limited observation, only 22% of identified rotors were associated with proximity to low voltage areas. The 12- and 24-month arrhythmia free rate was 93% (13/14) and 92% (12/13) for paroxysmal AF, 60% (9/15) and 47% (7/15) for persistent AF, and 70% (48/69) and 64% (43/67) for long-standing persistent AF, respectively, after a single FIRM procedure and re-isolation of the veins.

CONCLUSIONS

The data show a benefit for FIRM-guided ablation in recurrent AF at 12 months. No correlation was found between rotors and tissue characterization, AF duration, or previous number of ablations, suggesting that rotors may play an independent role in maintaining recurrent AF after prior failed ablation.

Acute and long-term outcome of redo catheter ablation for recurrent atrial tachycardia and recurrent atrial fibrillation in patients with prior atrial fibrillation ablation

PURPOSE

Organized atrial tachycardia (AT) accounts for a substantial proportion of recurrence after radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF). We sought to analyze the characteristics and long-term outcome of redo RFCA for recurrent AT compared with those for recurrent AF.

METHODS

We analyzed 133 patients who underwent prior AF ablation and presented for redo RFCA procedure. Documented rhythm at recurrence was AT in 50 patients (37.6%) and AF in 83 patients (62.4%). Redo ablation was conducted using a stepwise approach in all subjects.

RESULTS

Recurrent arrhythmia was more frequently a persistent type in the AT group (70.0% vs. 36.1% in the AT and AF group, respectively, p < 0.001). Fifty mappable ATs were identified in the AT group. Perimitral reentry was most common (19/50), followed by PV-related focal or reentrant tachycardia (16/50). During the redo RFCA, PV reconnection rate and linear ablation rate were similar in the two groups, while the focal target ablation tended to be conducted more frequently in the AF group (26.0% vs. 42.2%, p = 0.060). The AT group showed a higher acute success rate (92.0% vs. 75.9%, p = 0.019) and higher arrhythmia freedom during a mean of 30 months (76.0% vs. 55.4%, p = 0.030), compared with the AF group. The AT group and de novo AF type (paroxysmal) were independent predictors for higher arrhythmia freedom.

CONCLUSIONS

RFCA for recurrent AT following AF ablation showed favorable acute and long-term success rates and was associated with superior procedural outcomes compared with those for recurrent AF.

Alternative strategies to improve success rate of mitral isthmus block

Achieving bidirectional conduction block (BDB) across the mitral isthmus (MI) is technically challenging. We describe our experience using different ablation strategies for achieving successful MI block.We reviewed the records of patients who had undergone MI ablation for peri-mitral (PM) flutter at our institution from January 2010 to May 2015. We investigated ablation strategies for achieving MI block and their long-term outcomes in terms of recurrence of atrial tachyarrhythmia.Single endocardial MI ablation with or without distal coronary sinus (CS) ablation achieved MI block in 129 out of 236 (54.7%) patients. After failure of MI block, a new MI line ablation, ablation targeting the vein of Marshall (VOM), or anterior line ablation was performed in selected patients. The MI block was achieved in 13 (52.0%) out of 25 patients with new MI line ablation and in 13 (68.4%) out of 19 patients with VOM ablation. Anterior line ablation was tried in 23 patients and the line of block was achieved in 12 (52.2%) patients. Finally, overall PM BDB (PMB, MI block or anterior line block) was achieved in 167 (70.8%) of 236 patients. The incidence atrial tachyarrhythmia was similar between the patients with successful PMB and those with failed PMB (32.9% vs 42.0%, P = .18). In multivariable Cox regression analysis, the PMB was not associated with recurrence of atrial tachyarrhythmia (hazard ratio [HR]: 0.70, 95% confidence interval [CI]: 0.43-1.12).In conclusion, single endocardial MI line with or without distal CS ablation showed limited success for achieving MI block. Additional substrate modifications such as a new MI line ablation, anterior line ablation, or ablation targeting the VOM may improve the success rate of PMB block. However, the benefits of PMB were not clear in this study.

Insights into ablation of persistent atrial fibrillation: Lessons from 6-year clinical outcomes

INTRODUCTION

Ablation of persistent atrial fibrillation (AF) is a potential treatment option for symptomatic patients. We sought to evaluate the critical role of circumferential pulmonary vein isolation (CPVI) in the ablation of persistent AF.

METHODS AND RESULTS

A total of 341 ablation procedures were performed in 174 consecutive patients with persistent AF. CPVI was performed in all patients, additional ablation was only performed if electrical cardioversion failed after CPVI. During a median follow-up (FU) of 89 (63; 89) months, stable sinus rhythm was documented in 42/170 (25%) patients after a single procedure and in 111/164 (68%) patients after 1.9 ± 1.1 procedures. Stable SR was achieved in 40/75 (53%) patients in whom only CPVI was performed during the index and repeat procedures and in 71/89 (79%) patients with CPVI plus additional ablation. The main predictor for ablation success was duration of persistent AF before the index procedure (P < 0.001, HR ± CI: 1.608 [1.034, 1.103]). Responders to CPVI during the initial procedure had a significantly better multiple-procedure outcome after 42 months of FU compared to CPVI nonresponders (P  =  0.0365). Conversion during the index procedure had no impact on clinical outcomes (P  =  0.0903). Persistent AF regressed to paroxysmal AF in 16% of patients.

CONCLUSIONS

We demonstrate a 25% single- and 68% multiple-procedure success in patients with persistent AF, while stable SR was achieved in 53% of patients with pure CPVI during all procedures and in 79% of patients with CPVI plus additional ablation. Only duration of persistent AF before ablation had a statistically significant impact on ablation outcome.