Atrial high rate episodes as a marker of atrial cardiomyopathy: In the quest of the Holy Grail. Author's reply

Atrial cardiomyopathy: An entity of emerging interest in the clinical setting

Since 1995, the concept of atrial cardiomyopathy (ACM) has been associated with myocardial fibrosis. Despite a consensus document in 2016, ACM's definition primarily relies on histopathological findings. The focus on diagnostic criteria for ACM is driven by the potential link to thromboembolic events even independently on atrial fibrillation (AF). The complexity of the mutual relationships between ACM and AF makes difficult any assessment of the thromboembolic risk associated to ACM per se. ACM's thrombogenicity is a multifaceted clinical phenomenon involving electrical, functional, and structural modifications. Factors such as cardiovascular risk factors (e.g., hypertension), common cardiac comorbidities (e.g., heart failure), and extracardiac conditions (e.g., neuromuscular disorders) can promote atrial derangement, triggering atrial fibrillation (AF) and increasing the risk of thromboembolic events. Several diagnostic methods are available to detect the key features of ACM, including electrical changes assessed by surface and intracavitary ECG, and structural and functional alterations evaluated through echocardiography and cardiac magnetic resonance (CMR). These methods can be complemented by electro-anatomical mapping (EAM) to enhance the accuracy of myocardial tissue characterization and assessment of atrial fibrosis. Although certain clinical conditions (e.g., atrial high-rate episodes, AHREs; embolic stroke of undetermined source, ESUS) often exhibit atrial alterations in their thromboembolic presentations, recent randomized trials have failed to demonstrate the benefits of oral anticoagulation in patients with ACM without AF. However, ACM constitutes the substrate for the development of AF, as proposed in the AF European guidelines under the 4S-AF scheme. This review emphasizes the lack of a diagnostic gold standard and the need for clinical criteria for ACM, aiming to better understand the potential therapeutic implications of atrial structural and functional derangements, even in the absence of clinical evidence of AF.

Oral Anticoagulation in Patients With Atrial High-Rate Episodes: Focus on Clinical Implications

Background Although previous studies showed that atrial high-rate episodes (AHREs) are associated with a higher risk of developing incident atrial fibrillation (AF) and thromboembolic events, their clinical significance is still unclear. The purpose of this study was to define whether there is any clinical impact on the occurrence of ischemic and hemorrhagic events in patients with AHREs and initiation of oral anticoagulation (OAC). Methodology Patients with AHREs who had received cardiac implantable electronic devices (CIEDs, i.e., dual-chamber pacemaker [PM] or implantable cardioverter defibrillator [ICD]) were included in the study. OAC initiation was decided by the assistant doctor. Patients who received OACs comprised the OAC group, while patients who were not referred for OAC initiation were included in the control group. The primary endpoint was the time to the event of the occurrence of thromboembolic events (thromboembolic event-free survival). Results A total of 154 individuals (77 in each group) were enrolled in the study, with a mean age of 72.5 years. The mean follow-up period for the OAC group was 19.1 months and for the control group, 18.9 months (P = 0.9). Thromboembolic events were noticed only in seven patients. Six of them were in the control group, and only one in the OAC group (P = 0.05). Major bleeding events were noticed in five patients, one of whom was in the control group and the rest in the OAC group (P = 0.17). Conclusions OAC therapy in patients with AHREs was not associated with a significant difference in the risk of thromboembolic and bleeding events. Baseline patient characteristics and AHRE duration may be useful to intensify the monitoring and management of patients with AHREs. Bleeding events may be indicators of cancer in patients with AHREs receiving OACs.

New Perspectives on Risk Stratification and Treatment in Patients with Atrial Fibrillation: An Analysis of Recent Contributions on the Journal of Cardiovascular Disease and Development

The medical approach to atrial fibrillation (AF) underwent a paradigm shift over time, evolving from considering AF as a simple arrhythmic phenomenon to a complex nosological entity [...].

The performance of five models compared with atrial high rate episodes predicts new atrial fibrillation after cardiac implantable electronic devices implantation

Aims

Several predicting models have been evaluated for new‐onset atrial fibrillation (AF) in several clinical conditions, but never in patients with cardiac implantable electronic devices (CIED). We aimed to evaluate the five predicting models compared with atrial high rate episodes (AHRE) to predict new AF in patients with CIED.

Methods and Results

We retrospective enrolled 470 consecutive patients with CIED and without a history of AF. The five predicting models, including CHA₂DS₂‐VASc score, C₂HEST score, mCHEST score, HAT₂CH₂ score, and HAVOC score were used. The primary endpoint was new AF documented by 12‐lead electrocardiography (ECG) or 30‐s ECG strip. Multivariable Cox regression analysis was used to determine variables associated with independent factors of new AF. Patients' median age was 76 years and 58.7% were male. During follow‐up (median 29 months), 34 new AF occurred (incidence rate 2.99/100 patient‐years, 95% CI 1.67–6.20). Multivariable Cox regression analysis showed AHRE ≥6 min and 24 h, and HAT₂CH₂ score were independent predictors for new AF. Optimal AHRE cutoff value was 9.3 min with highest Youden index (AUC, 0.806; 95% CI, 0.722–0.889; p < .001). The AF occurrence rate of AHRE ≥9.3 min was 7 times AHRE <9.3 min (p < .001).

Conclusions

We compared 5 predicting models for new AF in patients with CIED and without a history of AF. AHRE ≥6 min and 24 h, and HAT₂CH₂ score were independent predictors for AF.