Clinical & Experimental Cardiology
Open Access
ISSN: 2155-9880
ISSN: 2155-9880
Peter Ott
Sarver Heart Center - Banner University Medical Center, USA
Scientific Tracks Abstracts: J Clin Exp Cardiolog
While clinical atrial fibrillation (AF), is a well-known risk factor for stroke, the therapeutic implications for device detected subclinical atrial fibrillation (SCAF) remain unknown. A review of 950 patients with the implanted loop recorder revealed an incidence of SCAF (> 6 minutes in duration) ranging from 22-34% at 18 months follows up. Most episodes were asymptomatic and brief (<30 minutes). Several studies in patients with implanted pacemaker or ICD showed an incidence of SCAF between 20-50% at 12-18 months follow up. Patients with SCAF had an increase in rates of thrombo-embolic (TE) complications (HR 2-2.5), resulting in an absolute TE risk of 1.0�??2.5%/year. The stroke risk was highest in patients with increased CHADS stroke risk score. A recent large trial showed increased stroke rates only in patients with SCAF > 24 hrs duration. In this trial only 25% of SCAF episodes were > 24 hours in duration. Furthermore, in several trials, only 10-20% had SCAF within 30 days prior to the TE event. The remainder had either no SCAF, SCAF > 30 days prior to, or SCAF only after the TE event. In patients with clinical AF, anticoagulation therapy has been shown to reduce the risk of stroke; the benefit/risk ratio is not clear for patients with SCAF. Two studies are currently underway (ARTESIA NCT01938248 �?? NOAH NCT02618577) randomizing patients with device detected SCAF (> 6 min) to anticoagulation therapy versus placebo or aspirin. At the present time, in light of unproven benefit, yet real bleeding risk, the use of anticoagulation therapy may best be limited to patients with SCAF > 24 hrs episode duration and increased CHADS/CHADSVAS score. Close monitoring for the development of prolonged AF episodes is warranted.