Lone Atrial Fibrillation: Does It Exist? A “White Paper” of the Journal of the American College of Cardiology
Given that the term “lone atrial fibrillation” (AF) was first introduced many decades ago to describe AF patients without detectable heart disease, does it have any relevance in the contemporary care of such patients?
The investigators reviewed the original studies that defined lone AF based on the absence of certain cardiopulmonary conditions. They analyzed later studies to determine whether the prevalence of lone AF changed over time in the context of improvements in diagnostic capabilities. The authors perused the knowledge base to determine whether lone AF patients differ from other AF patients with respect to the atrial substrate, sustaining mechanisms, heritability, prognosis, and response to treatment.
In the intervening years since the original description of lone AF, improvements in imaging and an increasing appreciation of AF pathophysiology led to a decrease in the prevalence of lone AF, from approximately 30% to 3%. The authors cite anatomic, imaging, and electrophysiologic studies that have documented the presence of an abnormal atrial substrate (fibrosis, low-voltage areas, and slow conduction) even in the absence of obvious heart disease. Genome-wide association studies have implicated common single nucleotide polymorphisms in the development of AF in various contexts and not only in “lone AF.”
The authors concluded that our understanding of the basis of AF, in concert with an improvement in our ability to diagnose increasingly subtle abnormalities in cardiac structure, render the term “lone AF” obsolete.
AF seems to require an abnormal substrate, as evidenced by studies that have demonstrated structural (and functional) abnormalities even in the absence of heart disease by conventional criteria. Since ‘lone AF’ is often used synonymously with ‘idiopathic AF,’ i.e., without a known cause, the authors’ assertion that the former be abandoned is well founded. As for the counter argument that the designation of lone AF may have some prognostic import, the authors’ recommendation that more validated risk stratification schemes (e.g., CHADS2) be used instead is also reasonable.
Keywords: Prevalence, Polymorphism, Single Nucleotide, Heart Conduction System, Genome-Wide Association Study, United States
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