Detection and management of atrial fibrillation after cryptogenic stroke or embolic stroke of undetermined source

Abstract

Cryptogenic stroke (CS) and embolic stroke of unknown source (ESUS) represent a major challenge to healthcare systems worldwide. Atrial fibrillation (AF) is commonly found after CS or ESUS. Independent of the mechanism of the index CS or ESUS, detection of AF in these patients offers the opportunity to reduce the risk of stroke recurrence by prescribing an anticoagulant instead of aspirin. The detection of AF may be pursued with different monitoring strategies. Comparison of monitoring strategies should take into account that AF detection rates reported in published studies, and then pooled in meta-analyses, are not only a function of the monitoring strategy itself, but also depend on patient-related, device-related, and study design-related factors. Once AF is found, the decision to anticoagulate a patient should be made on the basis of AF burden and the baseline risk of the patient. Empirical anticoagulation in patients with ESUS and no evidence of AF is an intriguing but still-unproven strategy and therefore should not be adopted outside of randomized clinical trials.Each year, >790 000 people experience a new or recurrent stroke in the United States. 1 The cause of ischemic stroke remains undetermined after hospitalization in 10% to 40% of cases; this is often referred to as "cryptogenic" stroke (CS). 2 Differences in the definition and diagnostic workup contribute to this variable incidence in published series. To mitigate this limitation, the term "embolic stroke of undetermined source" (ESUS) has recently been proposed to identify those cases where the etiology of nonlacunar ischemic stroke remains elusive after a standardized diagnostic pathway. 3 The prevalence of ESUS was 16% to 32% in a recently published series. 4 Hence, even after a standardized comprehensive evaluation, the cause of ischemic stroke remains elusive in a significant proportion of patients, thus representing a major challenge for treatment selection. | STROKE RECURRENCE IN PATIENTS WITH PRIOR CS AND ESUSIn a recent study, patients with CS had an ischemic stroke recurrence rate of 9.1% (range, 6.2%-12.0%), 24.0% (range, 19.1%-28.9%), and 31.9% (range, 25.2%-38.6%) at 1, 5, and 10 years, respectively. 5 Recurrent stroke in these patients was classified again as cryptogenic in 63% of cases. 5 Stroke recurrence rate in ESUS was also reported to be high and similar to CS. 6 Possible causes of stroke recurrence, irrespective of the mechanism of the index stroke, are paroxysmal atrial fibrillation (AF), arterial sources of thromboembolism (TE), patent foramen ovale (PFO), cardiac structural abnormalities, and other less common etiologies. Detection of AF after a CS or ESUS does not imply causality but still offers an opportunity for reducing the risk of stroke recurrence by prescribing oral anticoagulation (OAC). However, AF is often asymptomatic, paroxysmal, and difficult to detect with conventional tools. Several monitoring strategies have been investigated to detect asymptomatic AF after an ischemic stroke, including electrocardiography (...

Usefulness of P Wave Duration in Embolic Stroke of Undetermined Source

“…Because of the previously reported association between ESUS and SCAF, detection of SCAF has been used as a screening target [4,13,14]. Although various strategies and modalities for prolonged, continuous ECG monitoring have been attempted to improve SCAF detection efficacy, their results have been inconsistent and often controversial [4,[15][16][17][18][19].…”

“…Many investigators have tried to improve SCAF detection efficacy, for example, by investigating the impact of the AF burden or the potential influence of the ECG definition of AF [12,13]. However, these potential factors are largely dependent on the trigger, which has huge variations over time and is difficult to predict and document.…”

Use of insertable cardiac monitors for the detection of atrial fibrillation in patients with cryptogenic stroke in the United States is cost-effective

“…The vast majority of patients had CHADS 2 scores of 2, 3 or 4 (34.01%, 41.50% and 19.05%, respectively). Based on the findings of CRYSTAL-AF, with a 30% AF detection rate after 3 years and an assumed 96.1% diagnostic sensitivity of the ICM involved 1,35 , it was estimated that the "true" AF prevalence among this patient population was 31.2%. This estimate potentially reflects an upper range 36 and we explored the impact of lower assumptions via our sensitivity analysis.…”

Statement by a Working Group conceived by the Polish National Consultants in Cardiology and Neurology addressing the use of implantable cardiac monitors in patients after ischaemic embolic stroke of undetermined source

“…It is desirable that ECG monitoring initiated shortly after ESUS be prolonged, especially in the subpopulation with additional signs of atrial disease [17][18][19][20][21][22]. Supplementary diagnostic procedures should be initiated as soon as possible following the occurrence of stroke, in order to maximise the benefits of potentially indicated anticoagulation.…”

“…Considering these limitations, and the uncertainty about long-term benefit, it is suggested that only patients with the highest risk of AF occurrence should be referred for such diagnostic workup [18]. Observational studies consistently point to older age as the main risk factor of the occurrence/ recognition of AF after cryptogenic stroke [20].…”