Oral anticoagulation for subclinical atrial tachyarrhythmias detected by implantable cardiac devices: an international survey of the AF-SCREEN Group
Introduction
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, with an epidemiological profile characterized by higher incidence and prevalence in the elderly, [1] and clinical relevance dominated by the associated increased risk of stroke/systemic embolism (SEE) [[2], [3], [4]]. AF is frequently asymptomatic with a similar if not higher risk of associated adverse outcome in terms of stroke and mortality than symptomatic AF [4,5].
Cardiac implanted electrical devices (CIEDs) with an atrial lead or with capability of rhythm discrimination (i.e. implantable cardiac monitors, ICM) extend the capability to detect atrial tachyarrhythmias since they allow continuous monitoring of cardiac rhythm, with detection of AF and atrial high-rate episodes (AHREs) coupled with storage of arrhythmia electrograms in device memory for review and specific diagnosis. AHREs, currently defined as episodes of at least 5 min of atrial tachyarrhythmias/AF with an atrial rate > 180 bpm, are usually asymptomatic, discovered during routine device follow-up and classified in terms of duration of the longest single episode, or time spent in atrial tachyarrhythmias during a day (from minutes to hours) [[6], [7], [8], [9], [10], [11]]. The term “subclinical AF” (SCAF) is currently used for episodes of atrial tachyarrhythmias with duration between 5 min and 24 h, detected by a CIED in patients without clinical history or clinical symptoms of AF [4,9,10].
The association between CIED-detected atrial tachyarrhythmias of variable durations and stroke or systemic thromboembolism has been evaluated by several studies that together collected data on >22,000 patients [3,4,9,10,12,13]. These studies showed that AHREs with a duration ≥5–6 min are associated with a significant increase in the risk of stroke or systemic thromboembolism, although the risk is around half of the risk associated with clinical AF [14]. However, there is substantial uncertainty about management of these patients to reduce the risk of stroke or systemic embolism, and specifically about the risk-benefit ratio of oral anticoagulation in this specific setting [4,10]. At present, there is no evidence in support of or against prescription of oral anticoagulants (OAC) in patients at increased risk of stroke (intermediate to high risk according to CHA2DS2VaSC score) who present with AHREs of short duration, confirmed as atrial tachyarrhythmias/AF by electrogram assessment. Two randomized controlled trials are ongoing for evaluating the efficacy and risk-benefit ratio of oral anticoagulation vs no oral anticoagulation (aspirin alone as the comparator), in patients with CIED-detected AHRE (ARTESiA (NCT01938248) [15] and NOAH – AFNET 6 (NCT02618577) [16]. Before availability of the results of these randomized trials, we aimed to assess current practice around management of OAC therapy in patients with CIED-detected AHREs, using an on-line survey. Questions in the survey were designed to elucidate how physicians perceive the risk of stroke and systemic embolism in patient sub-groups with device-detected atrial tachyarrhythmias, focusing on decision making for anticoagulation.
Section snippets
Methods
The survey was distributed in two steps. First the invitation to participate in this anonymous, web-based survey was sent in August 2018 by email to the 158 members of the AF-SCREEN International Collaboration, a group created in 2016 to promote discussion and research about screening for unknown or under-treated atrial fibrillation as a way to reduce stroke and death [4] (http://www.afscreen.org/). A few weeks later, in October 2018, the same invitation was distributed through e-mails by
Results
Overall, 310 physicians completed the survey (59 AF-SCREEN members and 251 non-members). The geographical region of respondents was Europe in 76%, Asia/Oceania in 15% and North America in 8%. Survey respondent characteristics are shown in Table 1.
In the whole group, 20% of the respondents reported to be currently involved in the ARTESiA trial (22% among AF SCREEN members), 8.1% in NOAH trial (12% among AF SCREEN members), 3.5% in both trials (3.4% among AF SCREEN members), while 69% were not
Discussion
There is growing interest on the significance and management of atrial tachyarrhythmias detected by implanted devices, which is not surprising considering their frequent occurrence and association with an increased risk of stroke/SEE [4,9,10,12,13]. However, the relationship with stroke events appears to be complex, with evidence of a temporal dissociation between stroke and AHRE occurrence [4,7,17,18], and other indicators that SCAF and AHRE are acting both as risk factor and risk marker for
Conclusions
There is substantial heterogeneity in the perception of the risk of stroke/SEE associated with SCAF/AHRE of variable duration and this results in different propensity to institute OAC therapy in patients at risk, as assessed by the CHA2DS2VASc score. The threshold of AHRE burden or episode duration that would trigger institution of OAC is highly variable, and differs according to the clinical scenario (lower threshold in case of previous stroke), and in some cases according to specialty and
Declaration of Competing Interest
GB reported speaker’s fees of small amount from Biotronik, Boehringer Ingelheim, Boston and Medtronic.
JSH reported research grants Bristol-Myers Squibb, Pfizer, Bayer, Boehringer Ingelheim, Medtronic, Boston Scientific, and St Jude Medical.
RBS reported funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 648131), German Ministry of Research and Education (BMBF 01ZX1408A), and German Center for
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2020, European Journal of Internal MedicineCitation Excerpt :The survey was distributed in two steps. First the invitation to participate in this anonymous, web-based survey was sent in December 2019 by email to all 177 members of the AF-SCREEN International Collaboration, a group created in 2016 to promote discussion and research about screening for unknown or under-treated atrial fibrillation as a way to reduce stroke and death (http://www.afscreen.org/) [12,21,22]. In January and February 2020, the same invitation was distributed through e-mails, in two rounds, by AF-SCREEN members to a “convenience sample” of colleague health care professionals (HCPs), physicians, nurses or allied health professionals involved in care of patients with arrhythmias or stroke, including cardiologists, electrophysiologists, neurologists, internal medicine physicians or geriatricians, primary care physicians/general practitioners (PCP/GPs), nurses, pharmacists or other allied health professionals, as shown in Table 1.
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