Use of ambulatory electrocardiography for the detection of paroxysmal atrial fibrillation in patients with stroke

Background: Patients with stroke commonly undergo investigations to determi ne the underlying cause of stroke. These investigations often include ambul atory electrocardiography to detect paroxysmal atrial fibrillation. There i s conflicting evidence in the literature regarding whether routine ambulato ry electrocardiography should be performed in all or selected stroke patien ts. This paper reviews the available evidence on (1) the yield of ambulator y electrocardiography in detecting paroxysmal atrial fibrillation in patien ts with stroke or transient ischemic attack and (2) the effectiveness of an ticoagulation in preventing recurrent stroke in patients with paroxysmal at rial fibrillation. Methods: A MEDLINE search for primary articles was perfo rmed, and the references were reviewed manually. In addition, citations wer e obtained from experts. The evidence was systematically reviewed using the evidence-based methodology of the Canadian Task Force on Preventive Health Care. Results: Ambulatory electrocardiography can detect atrial fibrillati on not found on initial electrocardiogram in between 1% and 5 % of people w ith stroke. Ambulatory electrocardiography is generally safe. The risk of r ecurrent stroke in the setting of paroxysmal atrial fibrillation is uncerta in, but appears to be similar to that seen with chronic atrial fibrillation (about 12% per year). Therapy with warfarin may reduce this risk by about two-thirds as compared to placebo. The annual risk of major bleeding with w arfarin therapy is between 1% and 3% but rates for individual patients depe nd on various specific risk factors. Interpretation: There is insufficient evidence to recommend for or against the use of ambulatory electrocardiogra phy for the detection of paroxysmal atrial fibrillation in either selected or unselected patients with stroke (C Recommendation). There is fair eviden ce to recommend therapy with warfarin for patients with stroke and paroxysm al atrial fibrillation (B Recommendation).