To the Editor:
The discussion of how to manage Mrs. P, a 60 year old woman with atrial fibrillation (1), nicely reprised Sir William Osler’s 1907 advice: “Too much stress should not be laid upon arrhythmia per se in the absence of organic disease” (2).
As presented, however, Mrs. P’s evaluation did not adequately exclude organic disease: neither her body mass index nor a general description of her habitus was provided. Although her physicians obviously had access to this information, its omission from the case record suggests that an emerging correlate of atrial fibrillation, obstructive sleep apnea (OSA), was not considered as a potential exacerbating factor in her illness.
The prevalence of OSA in American adults is estimated as 20%, most of it undiagnosed, and most of it related to obesity (3). Hypothyroidism and alcohol ingestion, both of which Mrs. P had, are two of several additional risk factors.
As recently reviewed in JAMA, the role of OSA in cardiac disorders is receiving increasing attention, in part because OSA “frequently coexists undiagnosed in patients with cardiovascular disease” (4). Several physiological mechanisms plausibly link OSA and atrial fibrillation (4), but few studies have examined their clinical links. Of highest relevance for Mrs. P, however, Kanagala et al (5) found that untreated sleep apnea doubles the likelihood of atrial fibrillation recurring within 12 months of cardioversion, when compared to OSA patients receiving positive pressure treatment.
The effectiveness, and, therefore, cost-effectiveness, of testing for OSA in patients with atrial fibrillation is unknown. However, given that OSA is itself common, serious, and treatable, a case can be made for testing patients such as Mrs. P for sleep apnea, especially if they are obese, before consigning them to a lifetime of perhaps unnecessary warfarin therapy. Certainly a stronger case can be made for taking a sleep history in all patients with atrial fibrillation.
(1) Singer DE. A 60-year-old woman with atrial fibrillation. JAMA. 2003;290:2182-9.
(2) Osler W. The Principles and Practice of Medicine. 6th ed., revised. New York: D. Appleton, 1907;835.
(3) Young T, Peppard PE, Gottlieb DJ. Epidemiology of obstructive sleep apnea: a population health perspective. Am J Respir Crit Care Med. 2002;165:1217-39.
(4) Shamsuzzaman AS, Gersh BJ, Somers VK. Obstructive sleep apnea: implications for cardiac and vascular disease. JAMA. 2003;290:1906-14.
(5) Kanagala R, Murali NS, Friedman PA, Ammash NM, Gersh BJ, Ballman KV, Shamsuzzaman AS, Somers VK. Obstructive sleep apnea and the recurrence of atrial fibrillation. Circulation. 2003;107:2589-94.