Prolonged Cardiac Monitoring for Detection of Paroxysmal Atrial Fibrillation After Cerebral Ischemia
Atrial fibrillation (AF) is a common arrhythmia, and its prevalence continues to rise with the aging of the population.1 It is the most frequent cause of ischemic stroke in elderly patients.2 Strokes from AF tend to be more severe and disabling.3 Consequently, the societal effect of AF-related strokes is large.
Despite advances in our understanding of stroke mechanisms, 20% to 30% of all strokes remain cryptogenic.4 Many of them have an embolic pattern on brain imaging and, therefore, an occult embolic source is suspected. Reported rates of cryptogenic stroke recurrence vary across cohorts but may be high.5 On the basis of current evidence, we found that patients with cryptogenic stroke or transient ischemic attack (TIA) are generally treated with antiplatelet therapy and control of vascular risk factors.6 Although this therapeutic strategy is adequate for arterial sources of embolism, it might be insufficient if a cause of cardiac embolism has been missed.
AF is often paroxysmal and asymptomatic.7 In fact, paroxysmal AF (PAF) may be more prevalent than persistent AF among patients with stroke. In a large study of consecutive patients with TIA or stroke, nearly two thirds of cases of AF were paroxysmal.8 PAF carries the same risk of stroke as persistent AF.9 Brief, asymptomatic episodes of PAF can be difficult to detect by conventional methods (ie, ECG, Holter monitoring of short duration, patient-activated loop recorders). Thus, occult PAF is a likely candidate to explain at least some cases of cryptogenic stroke or TIA.10 This is particularly important because oral anticoagulation might be indicated in these cases.
Recent technological advances have made it possible to monitor for PAF in the ambulatory setting for prolonged periods of time (weeks, months, and even years). These devices are extremely sensitive and can uncover …