Does Oral Anticoagulation Therapy Reduce Thromboembolic Events or Mortality In Patients with Device-detected Subclinical Atrial Fibrillation? A Review
Atrial fibrillation is the most prevalent arrhythmia occurring in 1.5- 2% of the general population, and accounting for approximately 30% of all strokes. In 20-45% of atrial fibrillation-related strokes, the arrhythmia is not documented and the patient is asymptomatic from a cardiovascular standpoint, prior to the stroke. Subclinical Atrial Fibrillation (SCAF) is defined as asymptomatic or clinically silent atrial fibrillation. Patients with SCAF exhibit no symptoms during the episode of atrial fibrillation. SCAF is frequently detected by continuous electrocardiographic monitoring in patients without history of atrial fibrillation. Several studies have shown that atrial tachyarrhythmias incidentally detected by implantable cardiac devices such as Implantable Cardiac Defibrillator (ICD) and pacemaker, are associated with a two-fold increase in the risk of death or stroke. While there is strong evidence for the benefit of Oral Anticoagulation (OAC) therapy in reducing stroke risk in patients with clinically diagnosed atrial fibrillation, information is lacking regarding benefit in those with subclinical atrial fibrillation. The aim of this current review is to present the prevalence and predictors of SCAF and to assess the impact of anticoagulation on all-cause mortality and thromboembolic events in patients with implantable devices.