Time-dependent prediction of arrhythmia recurrences during long-term follow-up in patients undergoing catheter ablation of atrial fibrillation: The Leipzig Heart Center AF Ablation Registry

The Southern Brazilian Registry of Atrial Fibrillation (SBR-AF Registry): Predictors of Atrial Arrhythmia Recurrence after First-Time Catheter Ablation

BACKGROUND

Treatment of atrial fibrillation (AF) with catheter ablation (CA) has evolved significantly. However, real-world data on long-term outcomes are limited, particularly in low- and middle-income countries.

OBJECTIVE

This multicenter prospective cohort of consecutive patients aimed to evaluate the safety and efficacy of first-time CA for AF in Southern Brazil from 2009 to 2024.

METHODS

The primary outcome was any atrial tachyarrhythmia (ATA) recurrence. Multivariable Cox proportional hazards model assessed independent predictors of recurrence.

RESULTS

Among 1,043 patients (mean age 67.3 ± 11.3 years, 27.9% female), 75.5% had paroxysmal AF. At a median follow-up of 1.4 (1.0 - 3.4) years, 21.4% had ATA recurrence. Recurrence rates were 18.6% for paroxysmal and 29.8% for persistent AF, and 67.3% of events occurred within the first year after CA. Predictors of recurrence were persistent AF at baseline (hazard ratio [HR] 1.57, 95% confidence interval [CI] 1.15-2.13; p = 0.004), enlargement of left atrial diameter (HR 1.03, 95% CI 1.00-1.05; p = 0.033), and higher EHRA score of AF symptoms (HR 1.60, 95% CI 1.18-2.18; p = 0.003). Recurrence rates decreased over time according to the procedure's calendar year, with a 9% relative reduction per consecutive year (HR 0.91; p < 0.001). There was a 2.1% rate of procedure-related adverse events.

CONCLUSIONS

In the largest cohort study of consecutive AF ablations in Latin America, predictors of ATA recurrence were related to later stages of AF. Complication and recurrence rates were comparable to those in high-income countries, underscoring the global applicability of CA for AF management.

MicroRNAs as Prognostic Biomarkers for Atrial Fibrillation Recurrence After Catheter Ablation: Current Evidence and Future Directions

Atrial fibrillation (AF) is the most common cardiac arrhythmia encountered in clinical practice and is associated with significant morbidity and mortality. Even though catheter ablation has emerged as an available and effective treatment for AF, recurrence remains a significant challenge. This review presents the existing evidence on the prognostic role of microRNAs (miRNAs) in the prediction of AF recurrence after catheter ablation. We examined studies investigating the association between miRNA expression and post-ablation AF recurrence. Multiple miRNAs have been highlighted as potential biomarkers, which are involved in pathophysiological processes such as atrial remodeling, fibrosis, and inflammation. Despite some promising results, there has been significant heterogeneity across the studies. In this review, we demonstrate the potential miRNAs that can be routinely used as biomarkers of AF recurrence, and we identify areas that require further research to validate their clinical utility.

Predicting Early recurrence of atrial fibrilation post-catheter ablation using machine learning techniques

BACKGROUND

Catheter ablation is a common treatment for atrial fibrillation (AF), but recurrence rates remain variable. Predicting the success of catheter ablation is crucial for patient selection and management. This research seeks to create a machine learning model to forecast the early recurrence of atrial fibrillation following catheter ablation.

METHODS

A prospective longitudinal study was conducted using data from the Iranian AF registry. The dataset included 402 consecutive AF patients who underwent radiofrequency catheter ablation. The primary outcome was early recurrence of AF within 3 months' post-ablation. Data preprocessing and feature selection were performed, followed by the development and evaluation of various machine learning models. The CatBoost model was selected as the best-performing model.

RESULTS

The study population had a mean age of 57.30 ± 14.05 years, and 61.4% were male. AF recurrence occurred in 26.1% of patients. The CatBoost model, utilizing 35 features, achieved an accuracy of 92.5% in predicting AF recurrence. The model demonstrated high sensitivity (88.6%) and specificity (94.0%), with an area under the ROC curve of 0.96. Paroxysmal AF, BUN, Cr, age, mitral regurgitation, LA velocity, and mild valvular heart disease were among the most important predictive features.

CONCLUSION

Machine learning methods, particularly the CatBoost model, demonstrate high accuracy in predicting early catheter ablation outcomes in AF patients. The developed model has the potential to improve patient care and decision-making by identifying patients most likely to benefit from the procedure. Further studies with larger sample sizes and external validation are warranted to assess the generalizability of this method for catheter ablation outcome prediction in AF patients.

Multidisciplinary management strategies for atrial fibrillation

There has been a significant increase in the prevalence of atrial fibrillation (AF) over the past 30 years. Pulmonary vein isolation (PVI) is an effective treatment for AF, but research investigations have shown that AF recurrence still occurs in a significant number of patients after ablation. Heart rhythm outcomes following catheter ablation are correlated with numerous clinical factors, and researchers developed predictive models by integrating risk factors to predict the risk of recurrence of atrial fibrillation. The purpose of this article is to outline the risk scores for predicting cardiac rhythm outcomes after PVI and to discuss the modifiable factors that increase the risk of recurrence of AF, with the hope of further improving catheter ablation efficacy through preoperative identification of high-risk populations and postoperative management of modifiable risk factors.

Freedom from atrial arrhythmia and other clinical outcomes at 5 years and beyond after catheter ablation of atrial fibrillation: a systematic review and meta-analysis

AIMS

Catheter ablation of atrial fibrillation (AF) is now a mainstream procedure although long-term outcomes are uncertain. We performed a systematic review and meta-analysis of procedural outcomes at 5 years and beyond.

METHODS AND RESULTS

We searched PubMed and Embase and after the screening, identified 73 studies (67 159 patients) reporting freedom from atrial arrhythmia, all-cause death, stroke, and major bleeding at ≥5 years after AF ablation. The pooled mean age was 59.7y, 71.5% male, 62.2% paroxysmal AF, and radiofrequency was used in 78.1% of studies. Pooled incidence of freedom from atrial arrhythmia at 5 years was 50.6% (95%CI 45.5-55.7%) after a single ablation and 69.7% [95%CI (confidence interval) 63.8-75.3%) after multiple procedures. The incidence was higher among patients with paroxysmal compared with non-paroxysmal AF after single (59.7% vs. 33.3%, p = 0.002) and multiple (80.8% vs. 60.6%, p < 0.001) ablations but was comparable between radiofrequency and cryoablation. Pooled incidences of other outcomes were 6.0% (95%CI 3.2-9.7%) for death, 2.4% (95%CI 1.4-3.7%) for stroke, and 1.2% (95%CI 0.8-2.0%) for major bleeding at 5 years. Beyond 5 years, freedom from arrhythmia recurrence remained largely stable (52.3% and 64.7% after single and multiple procedures at 10 years), while the risk of stroke and bleeding increased over time.

CONCLUSION

Nearly 70% of patients having multiple ablations remained free from atrial arrhythmia at 5 years, with the incidence slightly decreasing beyond this period. Risk of death, stroke, and major bleeding at 5 years were low but increased over time, emphasizing the importance of long-term thromboembolism prevention and bleeding risk management.

Atrial fibrillation: Primary prevention, secondary prevention, and prevention of thromboembolic complications: Part 2

Atrial fibrillation (AF), the most common sustained cardiac arrhythmia, once thought to be benign as long as the ventricular rate was controlled, is associated with significant cardiac morbidity and mortality. Increasing life expectancy driven by improved health care and decreased fertility rates has, in most of the world, resulted in the population aged ≥65 years growing more rapidly than the overall population. As the population ages, projections suggest that the burden of AF may increase more than 60% by 2050. Although considerable progress has been made in the treatment and management of AF, primary prevention, secondary prevention, and prevention of thromboembolic complications remain a work in progress. This narrative review was facilitated by a search of MEDLINE to identify peer-reviewed clinical trials, randomized controlled trials, meta-analyses, and other clinically relevant studies. The search was limited to English-language reports published between 1950 and 2021. Atrial fibrillation was searched using the terms primary prevention, hyperthyroidism, Wolff-Parkinson-White syndrome, catheter ablation, surgical ablation, hybrid ablation, stroke prevention, anticoagulation, left atrial occlusion and atrial excision. Google and Google scholar as well as bibliographies of identified articles were reviewed for additional references. In these two manuscripts, we discuss the current strategies available to prevent AF, then compare non-invasive and invasive treatment strategies to diminish AF recurrence. In addition, we examine the pharmacological, percutaneous device and surgical approaches to prevent stroke as well as other types of thromboembolic events.

Detection of Heart Arrhythmia on Electrocardiogram using Artificial Neural Networks

The electrocardiogram, also known as an electrocardiogram (ECG), is considered to be one of the most significant sources of data regarding the structure and function of the heart. In order to obtain an electrocardiogram, the contractions and relaxations of the heart are first captured in the proper recording medium. Due to the fact that irregularities in the functioning of the heart are reflected in the ECG indications, it is possible to use these indications to diagnose cardiac issues. Arrhythmia is the medical term for the abnormalities that might occur in the regular functioning of the heart (rhythm disorder). Environmental and genetic variables can both play a role in the development of arrhythmias. Arrhythmias are reflected on the ECG sign, which depicts the same region regardless of where in the heart they occur; thus, they may be seen in ECG signals. This is how arrhythmias can be detected. Due to the time limits of this study, the ECG signals of individuals who were healthy, as well as those who suffered from arrhythmias were divided into 10-minute segments. The arithmetic mean approach is one of the fundamental statistical factors. It is used to construct the feature vectors of each received wave and interval, and these vectors offer information regarding arrhythmias in accordance with the agreed-upon temporal restrictions. In order to identify the heart arrhythmias, the obtained feature vectors are fed into a classifier that is based on a multilayer perceptron neural network. In conclusion, ROC analysis and contrast matrix are utilised in order to evaluate the overall correct classification result produced by the ECG-based classifier. Because of this, it has been demonstrated that the method that was recommended has high classification accuracy when attempting to diagnose arrhythmia based on ECG indications. This research makes use of a variety of diagnostic terminologies, including ECG signal, multilayer perceptron neural network, signal processing, disease diagnosis, and arrhythmia diagnosis.

Effect of Outcome Measures on the Apparent Efficacy of Ablation for Atrial Fibrillation: Why "Success" is an Inappropriate Term

INTRODUCTION

Different endpoint criteria, different durations of follow-up and the completeness of follow-up can dramatically affect the perceived benefits of atrial fibrillation (AF) ablation.

METHODS

We defined three endpoints for recurrence of AF post ablation in a cohort of 200 patients with symptomatic AF, refractory to antiarrhythmic drugs (AADs). A 'Strict Endpoint' where patients were considered to have a recurrence with any symptomatic or documented recurrence for ≥30 seconds with no blanking period, and off their AADs, a 'Liberal Endpoint' where only documented recurrences after the blanking period, either on or off AADs were counted, and a 'Patient-defined Outcome endpoint' which was the same as the Liberal endpoint but allowed for up to two recurrences and one repeat ablation or DCCV during follow-up. We also surveyed 50 patients on the waiting list for an AF ablation and asked them key questions regarding what they would consider to be a successful result for them.

RESULTS

Freedom from recurrence of atrial tachyarrhythmias (AT) at 5 years was 62% for the Strict Endpoint, 73% for the Liberal Endpoint, and 80% for the Patient-defined Outcome endpoint (p<0.001). Of the 50 patients surveyed awaiting AF ablation, 70% said they would still consider the procedure a success if it required one repeat ablation or one DCCV (p=0.004), and 76% would be accepting of one or two recurrences during follow-up (p<0.001).

CONCLUSION

In this study, the majority of patients still considered AF ablation a successful treatment if they had up to two recurrences of AF, one repeat procedure or one DCCV. Furthermore, a 'Patient-defined' definition of success lead to significantly different results in this AF ablation cohort when compared to conventionally used/guideline directed measures of success.

Surveys and Registries on Catheter Ablation of Atrial Fibrillation: Fifteen Years of History

Surveys and registries are widely used in medicine as valuable tools to integrate the information from randomized and observational studies. Early after its introduction in daily practice and parallel to its escalating popularity, catheter ablation of atrial fibrillation has been the subject of several surveys and registries. Over the years, relevant aspects associated with atrial fibrillation ablation have been investigated using these tools, including procedural safety and efficacy, discontinuation of anticoagulation therapy and risk of stroke postablation, and outcomes in special populations. The aim of this article is to provide a comprehensive review of the contributions offered by surveys and registries in catheter ablation of atrial fibrillation over the past 15 years.

Predicting recurrent atrial fibrillation after catheter ablation: a systematic review of prognostic models

AIMS

We assessed the performance of modelsf (risk scores) for predicting recurrence of atrial fibrillation (AF) in patients who have undergone catheter ablation.

METHODS AND RESULTS

Systematic searches of bibliographic databases were conducted (November 2018). Studies were eligible for inclusion if they reported the development, validation, or impact assessment of a model for predicting AF recurrence after ablation. Model performance (discrimination and calibration) measures were extracted. The Prediction Study Risk of Bias Assessment Tool (PROBAST) was used to assess risk of bias. Meta-analysis was not feasible due to clinical and methodological differences between studies, but c-statistics were presented in forest plots. Thirty-three studies developing or validating 13 models were included; eight studies compared two or more models. Common model variables were left atrial parameters, type of AF, and age. Model discriminatory ability was highly variable and no model had consistently poor or good performance. Most studies did not assess model calibration. The main risk of bias concern was the lack of internal validation which may have resulted in overly optimistic and/or biased model performance estimates. No model impact studies were identified.

CONCLUSION

Our systematic review suggests that clinical risk prediction of AF after ablation has potential, but there remains a need for robust evaluation of risk factors and development of risk scores.

Short-Time Estimation of Fractionation in Atrial Fibrillation with Coarse-Grained Correlation Dimension for Mapping the Atrial Substrate

Atrial fibrillation (AF) is currently the most common cardiac arrhythmia, with catheter ablation (CA) of the pulmonary veins (PV) being its first line therapy. Ablation of complex fractionated atrial electrograms (CFAEs) outside the PVs has demonstrated improved long-term results, but their identification requires a reliable electrogram (EGM) fractionation estimator. This study proposes a technique aimed to assist CA procedures under real-time settings. The method has been tested on three groups of recordings: Group 1 consisted of 24 highly representative EGMs, eight of each belonging to a different AF Type. Group 2 contained the entire dataset of 119 EGMs, whereas Group 3 contained 20 pseudo-real EGMs of the special Type IV AF. Coarse-grained correlation dimension (CGCD) was computed at epochs of 1 s duration, obtaining a classification accuracy of 100% in Group 1 and 84.0–85.7% in Group 2, using 10-fold cross-validation. The receiver operating characteristics (ROC) analysis for highly fractionated EGMs, showed 100% specificity and sensitivity in Group 1 and 87.5% specificity and 93.6% sensitivity in Group 2. In addition, 100% of the pseudo-real EGMs were correctly identified as Type IV AF. This method can consistently express the fractionation level of AF EGMs and provides better performance than previous works. Its ability to compute fractionation in short-time can agilely detect sudden changes of AF Types and could be used for mapping the atrial substrate, thus assisting CA procedures under real-time settings for atrial substrate modification.