Apixaban for Stroke prevention in Subclinical Atrial Fibrillation

The first thing you might say is, “Why’s should I care about subclinical Atrial Fibrillation, I work in Emergency Medicine?” Perhaps, this will guide us to making better decisions on anticoagulation in patients who present with their first episode of Atrial Fibrillation and we need to cardiovert them. The decision making process, other than for the highest risk patients is not that clear.

Atrial fibrillation is the most common arrhythmia we see in the emergency department. It is the leading cause of stroke(1) and although we reduce that risk with anticoagulation, we then increase the risk of potential bleeding(2). We need to weigh up these two risks and determine if we treat or not.

Subclinical atrial fibrillation is asymptomatic atrial fibrillation, or atrial fibrillation causing non-specific symptoms, that are not clinically detected, unless it is detected in continuous cardiac monitoring by implanted cardiac devices. It has been found to be present in more than 30% of some patient groups, increasing the stroke risk by a factor of 2.5(3). That stroke risk is only increased by about a half ( 1 percent per year) of the risk of patients with clinically detected atrial fibrillation.