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Updated: Jun 24, 2025

A New Single Chamber Implantable Defibrillator with Atrial Sensing: A Practical Demonstration of Sensing and Ease of Implantation
Published on: February 28, 2012
Management of atrial arrhythmias identified by cardiac devices
1UOS Week Cardiology, UOC Cardiology, San Giovanni Addolorata Hospital, Rome.
Insights
Subclinical atrial fibrillation (AF), detected by implantable devices, presents a lower thrombo-embolic risk than overt AF. Current guidelines lack clarity, necessitating individualized risk assessment over a simple presence/absence approach.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Devices
Background:
- Implantable cardiac devices reveal atrial fibrillation (AF) is more common than previously thought.
- Subclinical AF, also known as atrial high-rate events (AHREs), are asymptomatic episodes requiring clearer management guidelines.
Purpose of the Study:
- To evaluate the clinical significance and optimal therapeutic management of subclinical AF (AHREs).
- To address the uncertainty surrounding anticoagulant therapy decisions in patients with AHREs.
Main Methods:
- Review of recent randomized studies (NOAH-AFNET 6, ARTESIA) on subclinical AF.
- Analysis of thrombo-embolic risk and bleeding risk associated with anticoagulant therapy in AHRE patients.
Main Results:
- Subclinical AF carries a lower thrombo-embolic risk (approximately 1%) compared to clinically manifest AF.
- The risk of bleeding may outweigh the benefits of anticoagulation in many patients with AHREs.
Conclusions:
- Decisions regarding anticoagulant therapy for subclinical AF should move beyond a simple yes/no dichotomy.
- An individualized approach, quantifying episode burden (number, duration) and considering CHADSVASC score, is crucial for risk stratification.
Abstract:
Implantable cardiac devices have shown that atrial fibrillation (AF) is more frequent than previously assumed, with subclinical, asymptomatic, self-limiting manifestations called atrial high-rate events (AHREs) or subclinical AF. The clinical significance and correct therapeutic management of these episodes of subclinical AF is less well defined than in the case of clinically manifest AF. Two important randomized studies on the topic have recently been published, NOAH-AFNET 6 and ARTESIA, which, however, have not definitively clarified the topic. In patients with AHRE or subclinical AF, the average thrombo-embolic risk is lower than that in patients with clinically manifest AF and is ∼1%. For this reason, in these patients, the possibility that the benefit of anticoagulant therapy is overshadowed by the risk of bleeding is very high. Therefore, while waiting for new tools that allow a better stratification of low-risk patients, we must rely on individual clinical evaluation and overcome the qualitative dichotomy (AHRE yes vs. AHRE no), preferring instead an approach that is as quantitative as possible and takes into account the number of episodes, their duration, and the patient's CHADSVASC score, before deciding, in each individual case, whether or not to use anticoagulant therapy.
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