Recommendation 1 - OAC therapy for highly selected patients with subclinical AF (2018, updated from 2014)
We suggest that it is reasonable to prescribe OAC therapy for patients who are aged 65 or older, or with a CHADS2 score of ≥ 1 ("CHADS-65") who have episodes of subclinical AF lasting > 24 continuous hours in duration. Additionally, high-risk patients (such as those with recent embolic stroke of unknown source) with shorter-lasting episodes might also be considered for OAC therapy (Weak Recommendation, Low-Quality Evidence).

Recommendation 2 – At least 24 hours of ECG monitoring (2014)
For patients being investigated for an acute embolic ischemic stroke or TIA, we recommend at least 24 hours of ECG monitoring to identify paroxysmal AF potential candidates for OAC therapy (Strong recommendation, Moderate Quality Evidence).

Values and preferences (2014)
This recommendation places relatively high value on the facts that brain embolism can be the first manifestation of previously undiagnosed AF and stroke/TIA patients generally do not receive OAC unless AF is detected. This recommendation places relatively less weight on the absence of clinical trials evaluating OAC therapy among patients who have only very brief subclinical AF.

Recommendation 3 – For selected older patients, additional ambulatory monitoring (2014)
For selected older patients with an acute, non-lacunar, embolic stroke of undetermined source for which AF is suspected but unproven, we suggest additional ambulatory monitoring (beyond 24 hrs) for AF detection, where available, if it is likely that OAC therapy would be prescribed if prolonged* AF is detected (Conditional Recommendation, Moderate Quality Evidence) [*There are currently insufficient data to indicate what the minimum AF duration should be for OAC to be instituted, and expert opinion varies widely].

Values and preferences (2014)
This recommendation places high value on aggressively investigating selected patients with unexplained embolic stroke. The main rationale is to improve the identification of patients who would have an evidence-based change in management aimed at preventing recurrent strokes (i.e., switching from antiplatelet therapy to OAC therapy) if a clear diagnosis of AF is found. In cases where only very brief subclinical AF is detected, the role of OAC therapy is currently uncertain and treatment decisions should be individualized."