A Population-Based Study of Unexplained/Lone Atrial Fibrillation: Temporal Trends, Management and Outcomes

Abstract Background Previous studies on lone/unexplained AF did not exclude patients with contemporary secondary AF triggers. We characterized unexplained AF using a strict definition, and compared it to secondary AF. Methods In this population-based study, unexplained AF was defined by the lack of any identifiable triggering medical/surgical diagnosis. Comparisons by AF type (unexplained vs secondary), age-of-onset (≤/>65 years-old) and sex were undertaken. Data were acquired by linking 6 population databases maintained by the Alberta Ministry of Health over a 9-year period (April 2006–March 2015). The primary composite outcome of stroke, transient ischemic attack, thromboembolism and/or death was assessed. Results There were 33,150 incident AF diagnoses identified, including 1,145 (3.5%) patients with unexplained AF, 931 (81.2%) of whom were ≤65 years-old (2.8% of diagnoses, and 79% male). Unexplained AF patients less often received rate/rhythm control drugs (p Conclusions Using a strict contemporary definition of unexplained AF, this study shows that the condition is rare, male predominant, and has excellent event-free survival. However, the high rate of acute hospital utilization after diagnosis is concerning.