© 2007 European Society of Cardiology
A high prevalence of sleep disordered breathing in men with mild symptomatic chronic heart failure due to left ventricular systolic dysfunction
a Academic Unit of Sleep and Breathing, The Royal Brompton Hospital, National Heart and Lung Institute Imperial College, Sydney Street, London, United Kingdom
b Department of Cardiac Medicine, The Royal Brompton Hospital, National Heart and Lung Institute Imperial College, Sydney Street, London, United Kingdom
c Department of Cardiology, The Conquest Hospital The Ridge, Hastings, East Sussex, United Kingdom
* Corresponding author. Academic Unit of Sleep and Breathing and Department of Cardiac Medicine, National Heart and Lung Institute, Imperial College, Royal Brompton Hospital, Sydney Street, London SW3 6NP. Tel.: +44 20 7351 8027; fax: +44 20 7351 8911. E-mail address: alivazir{at}doctors.org.uk
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Abstract |
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Background: Sleep disordered breathing (SDB) is common in severe chronic heart failure (CHF) and is associated with increased morbidity and mortality. The prevalence of SDB in mild symptomatic CHF is unknown.
Aim: The aim of this study was to determine the prevalence and characteristics of SDB in male patients with NYHA class II symptoms of CHF.
Methods and results: 55 male patients with mild symptomatic CHF underwent assessment of quality of life, echocardiography, cardiopulmonary exercise, chemoreflex testing and polysomnography. 53% of the patients had SDB. 38% had central sleep apnoea (CSA) and 15% had obstructive sleep apnoea. SDB patients had steeper VE/VCO2 slope [median (inter-quartile range) 31.1 (28–37) vs. 28.1 (27–30) respectively; p=0.04], enhanced chemoreflexes to carbon dioxide during wakefulness [mean±sd: 2.4±1.6 vs. 1.5±0.7%VE Max/mmHg CO2 respectively; p=0.03], and significantly higher levels of brain natriuretic peptide and endothelin-1 compared to patients without SDB. No differences in left ventricular ejection fraction, percent predicted peak oxygen uptake, or symptoms of SDB were observed.
Conclusions: A high prevalence of SDB was found in men with mild symptomatic CHF. Patients with SDB could not be differentiated by symptoms or by routine cardiac assessment making clinical diagnosis of SDB in CHF difficult.
Key Words: Chronic Heart Failure • Obstructive Sleep Apnoea • Central Sleep Apnoea
Received November 11, 2005; Revised June 14, 2006; Accepted August 15, 2006