Nocturnal desaturation in patients with stable heart failure

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Abstract

Objective

To determine the prevalence of sleep disordered breathing within a United Kingdom heart failure population.

Subjects

104 patients and 21 matched normal volunteers.

Methods

Overnight home pulse oximetry with simultaneous ECG recording in the patient group; daytime sleepiness was assessed using the Epworth sleepiness scale (ESS); 41 patients underwent polysomnography to assess the validity of oximetry as a screening test for Cheyne-Stokes respiration.

Results

Home oximetry was a good screening test for Cheyne-Stokes respiration (specificity 81% sensitivity 87%). Patients with poorer New York Heart Association (NYHA) classes had higher sleepiness scores (p < 0.005). Twenty three patients had "abnormal" patterns of nocturnal desaturation suggestive of Cheyne-Stokes respiration. The mean (SEM) frequency of dips in Sao2 exceeding 4% was 10.3 (0.9) per hour in the patients and 4.8 (0.6) in normal controls (p < 0.005). Ejection fraction correlated negatively with dip frequency (r = -0.5. p < 0.005). The patient subgroup with >or=to 15 dips/hour had a higher mean (SEM) NYHA class (3.0 (0.2) v 2.3 (0.1), p < 0.05), and experienced more ventricular ectopy (220 (76) v 78 (21) beats/hour, p < 0.05). There was no excess of serious arrhythmia.

Conclusions

Nocturnal desaturation is common in patients with treated heart failure. Low ejection fraction was related to dip frequency. Lack of correlation between dips and ESS suggests that arousal from sleep is more important than hypoxia in the aetiology of daytime sleepiness in heart failure. Overnight oximetry is a useful screening test for Cheyne-Stokes respiration in patients with known heart failure.

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