Perera KS, et al. - Sub-clinical atrial fibrillation (SCAF) has been linked with a 2.5-fold increased risk of stroke via the Asymptomatic Atrial Fibrillation and Stroke Evaluation in Pacemaker Patients and the Atrial Fibrillation Reduction Atrial Pacing Trial (ASSERT), but less than 20% patients who had a stroke had SCAF in the prior 30-days. So, rather than the cause, researchers looked into whether SCAF is simply a risk marker for stroke. While it looks to be acting only as a risk marker in 40% of patients with SCAF and stroke, in many cases, SCAF seems to be causal.

Methods

• Stroke neurologists blindly judged all ischemic strokes cited in the ASSERT trial.
• These strokes were classified as cortical vs sub-cortical, and sub-typed using modified TOAST criteria.
• The modified Rankin Score was used to measure stroke severity.

Results

• SCAF was found in 14 of the 44 participants who suffered an ischemic stroke.
• Data showed that 57% of these strokes (n = 8) were judged to be cardioembolic, 36% to be lacunar (n = 5), and 7% (n = 1) to be large artery disease.
• However, a cardioembolic stroke occurred in 4 of 5 patients who had SCAF detected within 30 days before their index stroke.
• The average length of SCAF in these 4 patients was 6.0 ± 6.1 hours/day.
• Among patients with (2.7 ± 2.3) and without SCAF (2.3 ± 2.0), (P=.68), the mRS at 30 days was similar.