Progression of Subclinical AF: A Harbinger of Heart Failure

Subclinical atrial fibrillation (SCAF), defined as short asymptomatic episodes of AF, is typically found in patients with dual-chamber pacemakers or implantable cardioverter-defibrillators (ICDs) but is increasingly detected by other methods, including smartphone applications. Duration of SCAF (also called silent AF and atrial high-rate episodes) has been variously defined, with no agreed-upon minimum or maximum. Most studies of SCAF use a range between >5 minutes and 24 hours and have associated SCAF with stroke. To explore the association between progression of SCAF (i.e., lasting >24 hours or developing overt AF) and hospitalization for heart failure (HF), researchers analyzed data from the industry-supported ASSERT study, which identifi…