Anterior mitral line in patients with persistent atrial fibrillation and anterior scar: A multicenter matched comparison-The MiLine study

Different Approaches to Atrial Fibrillation Ablation in Heart Failure Patients: Temporal Trends and Clinical Outcomes

BACKGROUND

Catheter ablation of atrial fibrillation has been proven beneficial in patients with heart failure and reduced ejection fraction (HFrEF). On top of pulmonary vein isolation (PVI), additional ablation strategies such as empirical lines/posterior box/low voltage ablation (PVI+L/LVA) are often used. Whether PVI+L/LVA provides additional benefits in this population has never been systematically investigated.

OBJECTIVES

This study sought to analyze the temporal trends and comparative outcomes of PVI+L/LVA vs PVI alone.

METHODS

Patients with HFrEF undergoing atrial fibrillation ablation were retrospectively enrolled. The 2 coprimary endpoints were ventricular function recovery and atrial fibrillation recurrence-free survival at 1 year. The performance of PVI and PVI+L/LVA was compared in the overall population and in 2 matched groups. A sensitivity analysis for measured confounders was performed.

RESULTS

A total of 955 HFrEF patients (62.1 years, 24.4% female) from 9 international centers were included (PVI only 51.6% vs PVI+L/LVA 48.4%). At 12 months after the procedure, 62.3% of the patients remained free from arrhythmia recurrences and 65.4% experienced ventricular function recovery. Comparing PVI to PVI+L/LVA, no significant difference in the 2 coprimary endpoints was observed, neither in the overall nor in the matched cohorts. The use of PVI+L/LVA increased from 27% in 2013 to 68% in 2022. Patients undergoing PVI+L/LVA experienced more complications (3.8 vs 1.2%; P = 0.018).

CONCLUSIONS

Catheter ablation is associated with significant improvements in systolic function, irrespective of the ablation strategy used. The use of PVI+L/LVA in HFrEF patients is progressively expanding over time. Although the benefits of this practice remain unproven, it is associated with an increased risk of overall and nonvascular complications. These results warrant caution regarding the growing use of PVI+ in HFrEF patients.

Atypical Atrial Flutter: Electrophysiological Characterization and Effective Catheter Ablation

Atrial flutter (AFL), defined as macro-re-entrant atrial tachycardia, is associated with debilitating symptoms, stroke, heart failure, and increased mortality. AFL is classified into typical, or cavotricuspid isthmus (CTI)-dependent, and atypical, or non-CTI-dependent. Atypical AFL is a heterogenous group of re-entrant atrial tachycardias that most commonly occur in patients with prior heart surgery or catheter ablation. The ECG pattern is poorly predictive of circuit anatomy but may still provide mechanistic insight. AFL is difficult to manage medically and catheter ablation is the preferred treatment for most patients. Recent progress in technology and clinical electrophysiology has led to detailed characterization of re-entry circuits and effective ablation strategies. Combined activation and entrainment mapping are key to identifying the re-entry circuit. The presence of a slow-conducting isthmus, localized re-entry, dual-loop re-entry or bystander loops may lead to misleading activation maps but can be identified by electrogram examination and entrainment mapping. In the occasional patient without inducible AFL, substrate mapping in sinus rhythm may be a viable strategy. Long-term ablation success requires the creation of a transmural continuous lesion across a critical component of the re-entry circuit. Procedural endpoints include bidirectional conduction block across linear lesions and non-inducibility of atrial tachycardia. The present review discusses the epidemiology, mechanisms, ECG characteristics, electrophysiological characterization, and catheter ablation of atypical AFL.

A tailored substrate-based approach using focal pulsed field catheter ablation in patients with atrial fibrillation and advanced atrial substrate: Procedural data and 6-month success rates

BACKGROUND

Focal pulsed field ablation (F-PFA) integrated in electroanatomic mapping systems allows tailored lesion sets in patients with atrial fibrillation (AF).

OBJECTIVE

We aimed to determine feasibility, safety, and 6-month outcome of F-PFA for a tailored substrate-based catheter ablation approach in patients with AF and advanced atrial substrate.

METHODS

Consecutive patients with AF and advanced atrial substrate treated by an F-PFA system (CardioFocus) through contact force-sensing catheters integrated in electroanatomic mapping systems were prospectively enrolled. The tailored substrate-based catheter ablation approach included isolation of all pulmonary veins with wide area circumferential ablation, posterior wall isolation, mitral anterior line, and cavotricuspid isthmus ablation, according to substrate. At 6 months, feasibility, arrhythmia recurrence, and safety were evaluated.

RESULTS

In 83 patients (33% female; indexed left atrial volume, 44 ± 15 mL/m2; 80% persistent AF or atrial flutter [AFl]; 57% redo procedures), successful de novo pulmonary vein isolation was performed in 36 patients and pulmonary vein reisolation in 30 patients. Mitral anterior line was performed in 19 patients with atypical AFl or anterior low-voltage areas; posterior wall isolation was performed in 38 patients with low-voltage areas or evoked delayed electrograms during premature atrial extrastimuli; and cavotricuspid isthmus ablation was performed in 24 patients with typical AFl. Median procedural and fluoroscopy times were 115 and 7 minutes, respectively. No complications occurred. At 6 months, arrhythmia recurred in 30 of 83 patients (21 AF; 9 atypical AFl).

CONCLUSION

Tailored substrate-based F-PFA in patients with AF and advanced atrial substrate is safe and effective. Acute procedural success was 100% with 64% freedom from arrhythmias after 6 months.

Adjunctive Left Atrial Posterior Wall Isolation in Treating Non-Paroxysmal Atrial Fibrillation: An Updated Meta-Analysis of Randomized Clinical Trials

BACKGROUND

The clinical outcomes of adjunctive posterior wall isolation (PWI) beyond pulmonary vein isolation (PVI) for non-paroxysmal atrial fibrillation (AF) remain unclear. This meta-analysis was conducted to evaluate the role of PWI in non-paroxysmal AF by pooled analysis of most updated randomized controlled trials (RCTs).

METHODS

A literature search in PubMed, Embase, and the Cochrane Library was performed to identify RCTs comparing the outcomes of PVI with and without PWI in non-paroxysmal AF patients. The primary outcomes were recurrence rates of all atrial arrhythmias, AF, and atrial tachycardia/flutter (AT/AFL). The secondary outcomes included total procedure time, ablation time, fluoroscopy time and procedure-related complications. Estimated risk ratios (RRs) and 95% confidence intervals (CIs) were evaluated.

RESULTS

Nine RCTs with a total of 1,243 non-paroxysmal AF patients were included in our analysis. There were no significant differences in all atrial arrhythmias recurrence (RR: 0.86, 95% CI: 0.66-1.11, p = 0.24, I2 = 49%) and AF recurrence (RR: 0.74, 95% CI: 0.51-1.08, p = 0.12, I2 = 62%) between stand-alone PVI group and PVI plus PWI group. Adjunctive PWI increased the AT/AFL recurrence rate (RR: 1.62 95% CI: 1.08-2.42, p = 0.02, I2 = 0%). In the subgroup analysis, PWI using cryoballoon ablation was associated with a significantly lower recurrence rate of all atrial arrhythmias (p = 0.01) and AF (p = 0.02) recurrence and similar recurrence rate of AT/AFL (p = 0.15). Additional PWI was associated with an increased AT/AFL recurrence (p = 0.03) in patients with left atrial diameter (LAD) <44 mm. Adjunctive PWI needed longer ablation time, fluoroscopy time, and total procedure time. The incidence of procedural adverse events was low and similar between both groups.

CONCLUSION

Adjunctive PWI beyond PVI did not improve the freedom from all atrial arrhythmias and AF with an increased recurrence rate of AT/AFL in non-paroxysmal AF patients. The ablation energy and LAD might affect the clinical outcome of PWI. However, larger more RCTs were needed to verify our findings.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society.

Maintenance of sinus rhythm after electrical cardioversion to identify patients with persistent atrial fibrillation who respond favorably to pulmonary vein isolation: the pre-pacific study

Background

Pulmonary vein isolation (PVI) is successful in approximately 50% of patients with persistent atrial fibrillation (PsAF) at one year. Identifying pre-procedurally the patients who respond favorably to a PVI alone strategy could improve their management. The present study aims to assess the predictive value of clinical response to pre-ablation electrical cardioversion (ECV) to identify the responders to PVI.

Methods

Consecutive patients undergoing catheter ablation for PsAF were retrospectively classified, as "ECV successful" vs. "ECV failure", according to the rhythm of presentation after an ECV performed ≥4 weeks. Clinical and procedural data were analyzed in both groups according to the ablation strategy applied (PVI vs. PVI + substrate modification).

Results

In total, 58 patients (39.4%) had successful ECVs and 89 (60.6%) had failed ECV. Preprocedural characteristics were similar in both groups. Compared to the ECV failure group, patients with successful ECV presented less frequently (34% vs. 60%; P = 0.004) and less extended (21.3 ± 22.2% vs. 38.9 ± 27.4% of LA surface, P = 0.008) low-voltage areas. Over 55 ± 19 weeks of follow-up, AF-free survival was similar in both groups (72.7% vs. 67.8%, p = 0.39). PVI alone resulted in 83% AF-free survival among patients in the ECV successful group at 13 months.

Conclusion

In approximately 40% of patients with PsAF, sinus rhythm can be restored by ECV and maintained for at least 1 month prior to catheter ablation. This clinical response is associated with less abnormal substrate as identified by left atrial voltage mapping and a procedural success rate of >80% with PVI alone.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society.

Regional conduction velocities determined by noninvasive mapping are associated with arrhythmia-free survival after atrial fibrillation ablation

BACKGROUND

Atrial arrhythmogenic substrate is a key determinant of atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI), and reduced conduction velocities have been linked to adverse outcome. However, a noninvasive method to assess such electrophysiologic substrate is not available to date.

OBJECTIVE

This study aimed to noninvasively assess regional conduction velocities and their association with arrhythmia-free survival after PVI.

METHODS

A consecutive 52 patients scheduled for AF ablation (PVI only) and 19 healthy controls were prospectively included and received electrocardiographic imaging (ECGi) to noninvasively determine regional atrial conduction velocities in sinus rhythm. A novel ECGi technology obviating the need of additional computed tomography or cardiac magnetic resonance imaging was applied and validated by invasive mapping.

RESULTS

Mean ECGi-determined atrial conduction velocities were significantly lower in AF patients than in healthy controls (1.45 ± 0.15 m/s vs 1.64 ± 0.15 m/s; P < .0001). Differences were particularly pronounced in a regional analysis considering only the segment with the lowest average conduction velocity in each patient (0.8 ± 0.22 m/s vs 1.08 ± 0.26 m/s; P < .0001). This average conduction velocity of the "slowest" segment was independently associated with arrhythmia recurrence and better discriminated between PVI responders and nonresponders than previously proposed predictors, including left atrial size and late gadolinium enhancement (magnetic resonance imaging). Patients without slow-conduction areas (mean conduction velocity <0.78 m/s) showed significantly higher 12-month arrhythmia-free survival than those with 1 or more slow-conduction areas (88.9% vs 48.0%; P = .002).

CONCLUSION

This is the first study to investigate regional atrial conduction velocities noninvasively. The absence of ECGi-determined slow-conduction areas well discriminates PVI responders from nonresponders. Such noninvasive assessment of electrical arrhythmogenic substrate may guide treatment strategies and be a step toward personalized AF therapy.

Mechanistic Insights From Trials of Atrial Fibrillation Ablation: Charting a Course for the Future

Success rates for catheter ablation of atrial fibrillation (AF), particularly persistent AF, remain suboptimal. Pulmonary vein isolation has been the cornerstone for catheter ablation of AF for over a decade. While successful for most patients, pulmonary vein isolation alone is still insufficient for a substantial minority. Frustratingly, multiple clinical trials testing a diverse array of additional ablation approaches have led to mixed results, with no current strategy that improves AF outcomes beyond pulmonary vein isolation in all patients. Nevertheless, this large collection of data could be used to extract important insights regarding AF mechanisms and the diversity of the AF syndrome. Mechanistically, the general model for arrhythmogenesis prompts the need for tools to individually assess triggers, drivers, and substrates in individual patients. A key goal is to identify those who will not respond to pulmonary vein isolation, with novel approaches to phenotyping that may include mapping to identify alternative drivers or critical substrates. This, in turn, can allow for the implementation of phenotype-based, targeted approaches that may categorize patients into groups who would or would not be likely to respond to catheter ablation, pharmacological therapy, and risk factor modification programs. One major goal is to predict individuals in whom additional empirical ablation, while feasible, may be futile or lead to atrial scarring or proarrhythmia. This work attempts to integrate key lessons from successful and failed trials of catheter ablation, as well as models of AF, to suggest future paradigms for AF treatment.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society (HRS), the Asia Pacific HRS, and the Latin American HRS.

In Silico TRials guide optimal stratification of ATrIal FIbrillation patients to Catheter Ablation and pharmacological medicaTION: the i-STRATIFICATION study

AIMS

Patients with persistent atrial fibrillation (AF) experience 50% recurrence despite pulmonary vein isolation (PVI), and no consensus is established for secondary treatments. The aim of our i-STRATIFICATION study is to provide evidence for stratifying patients with AF recurrence after PVI to optimal pharmacological and ablation therapies, through in silico trials.

METHODS AND RESULTS

A cohort of 800 virtual patients, with variability in atrial anatomy, electrophysiology, and tissue structure (low-voltage areas, LVAs), was developed and validated against clinical data from ionic currents to electrocardiogram. Virtual patients presenting AF post-PVI underwent 12 secondary treatments. Sustained AF developed in 522 virtual patients after PVI. Second ablation procedures involving left atrial ablation alone showed 55% efficacy, only succeeding in the small right atria (<60 mL). When additional cavo-tricuspid isthmus ablation was considered, Marshall-PLAN sufficed (66% efficacy) for the small left atria (<90 mL). For the bigger left atria, a more aggressive ablation approach was required, such as anterior mitral line (75% efficacy) or posterior wall isolation plus mitral isthmus ablation (77% efficacy). Virtual patients with LVAs greatly benefited from LVA ablation in the left and right atria (100% efficacy). Conversely, in the absence of LVAs, synergistic ablation and pharmacotherapy could terminate AF. In the absence of ablation, the patient's ionic current substrate modulated the response to antiarrhythmic drugs, being the inward currents critical for optimal stratification to amiodarone or vernakalant.

CONCLUSION

In silico trials identify optimal strategies for AF treatment based on virtual patient characteristics, evidencing the power of human modelling and simulation as a clinical assisting tool.

Atrial fibrillation cycle-length (AF-CL) inside the pulmonary veins predicts paroxysmal AF ablation success- the INDUCE-AF study

BACKGROUND

A novel method to measure atrial fibrillation cycle length (AF-CL) was recently described, based on the average of 10 consecutive signals (FARS10). FARS10 accurately identified pulmonary vein isolation (PVI)-responders among patients with persistent AF. Whether this method is applicable to patients with paroxysmal AF is unknown.

OBJECTIVE

The aim of this study is to evaluate the prognostic value of FARS10 measurements in patients with paroxysmal AF.

METHODS AND RESULTS

We enrolled paroxysmal AF patients undergoing PVI in a prospective multicenter study. After AF induction with a standardized protocol, the AF-CL was measured using FARS-10 method. The primary endpoint was AF/AT-recurrence. One-hundred and four patients were included (61 ± 14 years, 25% females). After a mean follow-up of 12 ± 4 months, AF/AT recurrence rate was 20%. The fastest PV CL (fPV-CL) was independently associated with the primary endpoint at multivariate analysis (HR 1.02, p < 0.001). Every 10 ms increase in fPV-CL, AF recurrences increased by 20%. The value of 160 ms was found to be the optimal cut-off (specificity 81%, sensitivity 76%). Patients with fPV-CL < 160 ms experienced lower AF recurrences as compared to patients with fPV-CL > 160 ms (8% vs. 32% at 1 year; HR = 0.17, p < 0.001). Progression to persistent AF was observed in 13% of patients with fPV-CL > 160 ms.

CONCLUSION

fPV-CL measured with the FARS-10 method accurately predicts PVI success in paroxysmal AF patients undergoing PVI. Patients with slow PV activity (fPV-CL > 160 ms) experience higher AF recurrence rate after PVI and more frequent progression to persistent AF.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society .

Predictive value of valvular calcification for the recurrence of persistent atrial fibrillation after radiofrequency catheter ablation

BACKGROUND

Valvular calcification (VC) is an independent risk factor for cardiovascular diseases. The relationship between VC and atrial fibrillation is not clear.

HYPOTHESIS

We treated the aortic valve, mitral valve, and tricuspid valve as a whole and considered the possible association between VC and recurrence of persistent atrial fibrillation (PsAF) after radiofrequency catheter ablation (RFCA).

METHODS

This study involved 2687 PsAF patients who underwent RFCA. Data were collected to explore the relationship between VC and outcome. VC was defined by echocardiography in aortic valve, mitral valve, or tricuspid valve. After 1 year follow-up, subgroup analysis, mixed model regression analysis, and score system analysis were performed. The external validation of 133 patients demonstrated the accuracy of this clinical prediction model.

RESULTS

Overall, 2687 inpatients were assigned to the recurrence group (n = 682) or the no recurrence group (n = 2005) with or without VC. Compared to patients with no recurrence, the incidence of VC was higher in recurrence patients. Recurrence was present in 18.5%, 34.9%, 39.3%, and 52.0% of the four groups, which met VC numbers of 0, 1, 2, and 3, respectively. After adjustment for potential confounding factors, VC was an independent risk factor for AF recurrence in several models. For multivariable logistic regression, a scoring system was established based on the regression coefficient. The receiver operating characteristic area of the scoring system was 0.787 in the external validation cohort.

CONCLUSIONS

VC was an independent risk factor for AF recurrence in PsAF after RFCA. The scoring system may be a useful clinical tool to assess AF recurrence.

Gender-Related Differences in Atrial Substrate in Patients with Atrial Fibrillation

Gender-related differences have been reported in patients who underwent pulmonary vein isolation (PVI). Atrial substrate plays a role in the outcomes after ablation but gender-related differences in atrial substrate have never been described in detail. We sought to analyze gender-related differences in atrial remodeling (spontaneous low-voltage zones [LVZs]) and their clinical relevance after PVI. We conducted a prospective multicenter study, including consecutive patients who underwent first PVI-only atrial fibrillation (AF) ablation. LVZs were analyzed on high-density electroanatomical maps collected with multipolar catheter, before PVI. In total, 262 patients (61 ± 11 years, 31% female, 50% persistent AF) were followed for 28 months. In women, LVZs were larger (10% vs 4% of left atrial surface [p <0.001]) and female gender was independently associated with fourfold higher risk of having advanced (LVZ > 15%) atrial remodeling (odds ratio 4.56, p <0.001). AF recurrence-free survival was not different between men and women (log-rank p = 0.2). Although LVZs were independently associated higher AF recurrences at multivariate analysis (hazard ratio [HR] 1.2, p = 0.038), female gender was not (HR 1.4, p = 0.211). Specifically, the LVZ cutoff to predict outcomes was different in men and women: >5% in men (HR 3.0, p <0.001), >15% in women (HR 2.7, p = 0.02). In conclusion, women have more widespread LVZ in all left atrial regions. Despite more extensive atrial remodeling, the AF recurrence rate is similar in men and women, and LVZs become prognostic in women only at high burden (>15%). LVZs seem to have a different prognostic role in men and women.

Left atrial anterolateral linear ablation for biatrial tachycardia via Bachmann's bundle, interatrial septum, and left atrial anterior wall under mitral isthmus block

Biatrial tachycardia via Bachmann's bundle, interatrial septum, and left atrial anterior wall can be treated by left atrial anterolateral linear ablation without left atrial appendage isolation, even under mitral isthmus block.