Aims and objectives:~The goal of this study is to evaluate left atrial structural and functional abnormalities in patients with stroke of likely cardio-embolic origin compared with healthy age and sex matches controls and patients with atherosclerotic stroke using cardiac MRI.~Background:~Despite standard work up for the etiology of ischemic stroke, about 30% of the cases remain unexplained. It is increasingly accepted that these unexplained cases arise from disease outside of the brain. Paroxysmal AF (Atrial fibrillation) may often be suspected as the source but fewer than one third of patients with stroke of undetermined source manifest AF in any form even after 3 years of continuous heart rhythm monitoring. Emerging evidence suggest that atrial functional and structural abnormalities may convey a comparable risk of stroke in which AF is only one of several features. These abnormalities have been termed atrial cardiomyopathy and may be an efficient and practical approach to identify patients at high risk of AF and ischemic stroke.~Methods and materials:~Cross sectional and prospective cohort study with 3 different groups: 50 patients with stroke of undetected mechanism, 50 patients with atherosclerotic stroke (large or small vessel disease) admitted to the University Hospital of Bispebjerg and Frederiksberg and 50 sex and age matched controls with no history of stroke or AF from the Copenhagen City Heart Study (ØBUS) will be included during a 2 year-period. The study will measure atrial structural abnormalities using cardiac magnetic resonance imaging (MRI) and atrial functional abnormalities by cardiac MRI and echocardiography. A 1 year follow up will examine the incidence of silent brain infarction with MRI and incidence of stroke, atrial fibrillation, acute myocardial infarction and cardiovascular death. Secondary endpoints are to examine the association of functional and structural changes found by MRI with echocardiography, rhythm abnormalities and biomarkers with the purpose of finding clinical easily applicable methods to diagnose atrial cardiomyopathy.~Expected outcome and perspectives:~The investigators hypothesize that patients with stroke of likely cardio-embolic origin have significantly more atrial fibrotic degeneration and reduced atrial emptying function than patients with atherosclerotic stroke and the control subjects. The investigators expect a higher incidence of silent brain infarction in the group with stroke of likely cardio-embolic origin. With atrial cardiomyopathy investigated thoroughly in patients with stroke of likely cardio-embolic origin the future work-up and treatment strategies could be more efficient and may thus improve the prognosis in terms of mortality and disability for a considerable number of patients.
The goal of this study is to evaluate left atrial structural and functional abnormalities in stroke of undetected mechanism and atherosclerotic stroke with cardiac MRI.