Cryptogenic stroke due to undetected atrial fibrillation—longer ECG monitoring may be the key

Up to 40% of ischemic strokes remain unexplained after routine evaluation and thus are considered cryptogenic. However, a number of these strokes may be due to an undetected episode of paroxysmal atrial fibrillation (AF) where anticoagulation can reduce the risk of subsequent ischemic stokes. Although a minimum of 24 hours of ECG monitoring is guideline recommended in the evaluation of ischemic stroke to identify AF, the optimal duration of monitoring remains undetermined. Among patients with cryptogenic stroke, two concurrent publications evaluated the AF diagnostic yield of extended ECG monitoring.

In the first study, 572 patients with a history of cryptogenic stroke or transient ischemic attack in the prior 6 months were randomized to 30-day event triggered ECG monitoring or 24-hour ECG monitoring. Among patients with 30-day monitoring, an episode of AF lasting at least 30 seconds was identified …