Diagnosis of atrial fibrillation in young patients with ischemic stroke: A systematic review and meta-analysis

Introduction: The recommended cardiac rhythm evaluation to determine the etiology of ischemic stroke (IS) is similar in all patients regardless of their age and includes an electrocardiogram and at least a 24-hour heart rhythm monitoring. However, it is known that the main causes of IS vary according to patients' age. There is a higher preponderance of arterial dissections and patent foramen ovale in younger patients, while atrial fibrillation (AF) is more common in older patients.Aims: To determine the proportion of AF in young IS reported in the literature and determine if young IS patients found to have AF had known structural cardiac pathology.Methods: Systematic review of the literature searching PubMed and Embase for articles published since their inception to August 2020. Inclusion criteria were studies including at least 10 patients, aged 14-50 years-old, clinical or radiological diagnosis of IS and quantification of patients found to have AF. We conducted a meta-analysis using a random-effects model and calculated pooled proportions with 95% confidence intervals.Results: 8331 articles were screened, 154 were selected for full-text review. 43 studies were included in our final analysis (902800 patients). The proportion of AF in young IS overall was 3.1% [95%CI 2.4-3.7], I2 93.88%. Sub-analysis revealed a proportion of AF of 3.8% [95% CI 0.3-7.3] in lower-middle-income economies, versus 5.4% [95% CI 3-7.9] in upper-middle-income economies, and 2.2% [95% CI 1.6-2.8] in high-income economies. Only 3 studies mentioned the proportion of patients with AF that had structural cardiac pathology.Conclusion: The proportion of AF in young IS was low. More studies are needed to better understand if young IS patients diagnosed with AF had a priori known structural cardiac pathology that could increase the probability of finding AF. This could lead to a reevaluation of the need for 24 hours cardiac rhythm evaluation in young patients without cardiac pathology.