Chest
Volume 141, Issue 4, April 2012, Pages 967-973
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Original Research
Sleep Disorders
Sleep-Disordered Breathing and Excessive Daytime Sleepiness in Patients With Atrial Fibrillation

https://doi.org/10.1378/chest.11-0975Get rights and content

Background

An important consequence of sleep-disordered breathing (SDB) is excessive daytime sleepiness (EDS). EDS often predicts a favorable response to treatment of SDB, although in the setting of cardiovascular disease, particularly heart failure, SDB and EDS do not reliably correlate. Atrial fibrillation (AF) is another highly prevalent condition strongly associated with SDB. We sought to assess the relationship between EDS and SDB in patients with AF.

Methods

We conducted a prospective study of 151 patients referred for direct current cardioversion for AF who also underwent sleep evaluation and nocturnal polysomnography. The Epworth Sleepiness Scale (ESS) was administered prior to polysomnography and considered positive if the score was ≥ 11. The apnea-hypopnea index (AHI) was tested for correlation with the ESS, with a cutoff of ≥ 5 events/h for the diagnosis of SDB.

Results

Among the study participants, mean age was 69.1 ± 11.7 years, mean BMI was 34.1 ± 8.4 kg/m2, and 76% were men. The prevalence of SDB in this population was 81.4%, and 35% had EDS. The association between ESS score and AHI was low (R2 = 0.014, P = .64). The sensitivity and specificity of the ESS for the detection of SDB in patients with AF were 32.2% and 54.5%, respectively.

Conclusions

Despite a high prevalence of SDB in this population with AF, most patients do not report EDS. Furthermore, EDS does not appear to correlate with severity of SDB or to accurately predict the presence of SDB. Further research is needed to determine whether EDS affects the natural history of AF or modifies the response to SDB treatment.

Section snippets

Subjects

From June 2004 to April 2009 we conducted a prospective study of patients referred to the Mayo Clinic Center for Sleep Medicine for a sleep evaluation following DCCV treatment of AF. A total of 151 patients who underwent in-laboratory-attended polysomnography were included in the analysis. Echocardiography generally was performed prior to DCCV. This study was approved by the Mayo Clinic Institutional Review Board (IRB-#1646).

Daytime Sleepiness

To assess the degree of daytime sleepiness, all patients completed the

Results

Demographic characteristics of all subjects according to the presence or absence of EDS are reported in Table 1. Mean age was 69.1 ± 0.9 years, mean BMI was 34.1 ± 0.7 kg/m2, and 76% of the patients were men. The mean left ventricular ejection fraction was 55.3% ± 1.1%; only 14% of the subjects had a left ventricular ejection fraction of ≤ 40%. The overall prevalence of SDB was 81.4%. OSA, as defined by an AHI of ≥ 5 events/h, was present in 57% of the subjects; using an AHI cutoff of ≥ 15

Discussion

The present study demonstrates that SDB is highly prevalent in patients with AF referred for sleep evaluation following DCCV who, despite marked elevations in the AHI, generally do not report subjective daytime sleepiness. Furthermore, EDS does not correlate with the presence or absence of SDB. Given the very high prevalence of SDB in patients with AF, the lack of sleepiness cannot be used to rule out the presence of SDB.

The data suggest that typical symptoms such as EDS cannot be relied on as

Acknowledgments

Author contributions: Drs Albuquerque, Calvin, Sert Kuniyoshi, Somers, and Caples had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Dr Albuquerque: contributed to the study concept and design; data acquisition, interpretation, and analysis; drafting of the manuscript; and critical revision of the manuscript.

Dr Calvin: contributed to the study concept and design; data acquisition, interpretation, and

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    Funding/Support: This work was supported by the Mayo Clinic Clinician-Investigator Training Program; Mayo Foundation; American Heart Association [Grant 04-50103Z]; National Heart, Lung, and Blood Institute [Grants HL65176, HL70302, HL73211, and HL099534]; the National Center for Research Resources (NCRR) [Grant 1ULI RR024150], a component of the National Institutes of Health (NIH); IGA of Ministry of Health No. NS10098-4/2008; European Regional Development Fund-Project FNUSA-ICRC [No. CZ.1.05/1.1.00/02.0123]; and the NIH Roadmap for Medical Research.

    Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (http://www.chestpubs.org/site/misc/reprints.xhtml).

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