Underutilization of Ambulatory ECG Monitoring After Stroke and Transient Ischemic Attack Missed Opportunities for Atrial Fibrillation Detection

Background and Purpose-Detection and treatment of atrial fibrillation is a major goal in secondary stroke prevention. Guidelines recommend at least 24 hours of ECG monitoring after stroke. However, it is unclear how often this is done in routine practice. Methods-In this longitudinal cohort study using data from the Ontario Stroke Registry, we analyzed consecutive patients presenting to designated stroke centers in Ontario, Canada (2003-2013) with a first acute ischemic stroke or transient ischemic attack (TIA) in sinus rhythm and without known atrial fibrillation. The primary outcome was the proportion of patients who received at least 24-hour Holter monitoring within 30 days after stroke/TIA. Secondary analyses assessed total duration of ECG monitoring completed within 90 days after stroke/TIA, temporal trends in monitoring use, and use of Holter monitoring relative to echocardiography. Results-Among 17 398 consecutive eligible patients (mean age 68.8 +/- 14.3 years), 30.6% had at least 24 hours of Holter monitoring within 30 days after stroke/TIA. Less than 1% of patients received prolonged monitoring beyond 48 hours. The median time to start monitoring was 9 days poststroke (interquartile range 3-25). Stroke/TIA patients were nearly twice as likely to receive an echocardiogram than a Holter monitor within 90 days (odds ratio 1.8, 95% confidence interval 1.67-2.01). Conclusions-Less than one third of patients in our cohort received guideline-recommended 24-hour Holter monitoring, and < 1% received prolonged ambulatory ECG monitoring. These findings highlight a modifiable evidence-practice gap that likely contributes to an overdiagnosis of strokes as cryptogenic, an underdiagnosis of atrial fibrillation, and missed anticoagulant treatment opportunities for secondary stroke prevention.