Atrial fibrillation (AF) is the most common heart rhythm disorder. Its name comes from the fibrillation (i.e. quivering) of the two upper chambers (atria) of the heart instead of a coordinated contraction, causing a rapid, irregular heart rate. This irregular contraction is ineffective, leading to the development clots in the heart. These clots can travel through the bloodstream until they get stuck in a brain artery. Millions of brain cells that depend on the oxygen supplied by the blocked artery die within minutes. This is known as a stroke. Strong blood thinners known as anticoagulants can lower stroke risk by 64% in AF patients when the AF is detected on an electrocardiogram (ECG) or if it lasts more than 24h on a heart monitor. Therefore, doctors use cardiac monitors to record the heartbeats of stroke patients for up to 3 years. It was historically thought, but not proven, that if AF was found in stroke patients, using anticoagulants could prevent a second stroke. However, recent information suggests that using cardiac monitors in stroke patients increases AF detection and anticoagulants prescription without a reduction in the number of new strokes. The failure to prevent a second stroke is likely the consequence of cardiac monitors sometimes detecting very short-duration AFs, which may have a low risk of stroke. If AFs last only for a few minutes or hours, anticoagulants may not be needed.

This study will assess if it is possible to organize a large clinical trial comparing the use of long-term vs. shorter-term heart monitoring. We will evaluate 24 patients in the same way we plan to evaluate a larger number of participants (>1000) in a future study. This will allow us to learn if such a study is possible, identify potential implementation challenges, and develop strategies to overcome those difficulties.