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/VCO 2 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 CO 2 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.
The symptom burden resulting from sleep-disordered breathing (SDB) in patients with mild-to-moderate congestive heart failure (CHF) is unclear. The current authors monitored 24-h activity levels and compared subjective and objective measures of daytime sleepiness in 39 CHF patients, New York Heart Association class 2-3, on optimal medication. A total of 22 patients were classified as SDB (apnoea/hypopnoea index (AHI) median (range) The duration of daytime activity was significantly shorter in the SDB group compared with the NoSDB group. The SDB group also had increased time in bed and poorer sleep quality, as shown by the fragmentation index. Objectively the SDB group when compared with the NoSDB group were significantly sleepier, subjectively the groups did not differ. The amount of napping was similar for both groups.Despite the lack of subjective symptoms of daytime sleepiness, congestive heart failure patients with sleep-disordered breathing were objectively sleepier during the day and had reduced daytime activity with longer periods in bed and poorer sleep quality when compared with those without sleep-disordered breathing.
In patients with obstructive sleep apnoea (OSA), the very low frequency power spectral density index (VLFI) derived from analysis of heart rate correlates with the severity of obstructive apnoeas. VLFI is also associated with Cheyne-Stokes respiration/central sleep apnoea (CSR/CSA) in congestive heart failure (CHF). The present authors have tested the hypothesis that per cent VLFI, derived from a standard Holter ECG recording, can be used to detect the presence of OSA and CSR/CSA in patients with mild-to-moderate CHF.In total, 60 CHF patients underwent polysomnography with monitoring of heart rate. Data from 33 patients were analysed for per cent VLFI. Of the 60 patients, 27 were excluded due to atrial fibrillation, extensive pacing or frequent ventricular extra systoles.Receiver operator characteristic curves were constructed to establish the per cent VLFI that would optimally identify the presence or absence of sleep-disordered breathing. Using an apnoea-hypopnoea index .20 events?h -1 and setting the per cent VLFI at 2.23% yielded a sensitivity of 85%, specificity of 65%, positive predictive value of 61% and a negative predictive value of 87%. The latter increased to 100% when using an apnoea-hypopnoea cut-off of 30 events?h -1 . In conclusion, these results suggest that spectral analysis of heart rate may be useful as a ''ruleout test'' for sleep-disordered breathing in patients with mild-to-moderate congestive heart failure.
A single night of cardiorespiratory monitoring is representative of moderate-to-severe SDB in patients with CHF. However, a high proportion of patients shift their type of SDB over 4 nights. These findings may have implications for the management of SDB in CHF.
In CHF patients with SDB, HCVR was reduced in the morning compared with the evening. However, removal of SDB for 1 night did not reverse the reduced HCVR. The relatively low morning HCVR could be linked with an increased risk of stroke.
Introduction: Heart failure (HF) patients with sleep disordered breathing (SDB) are no sleepier than those without SDB. We previously demonstrated that this may be due to reduced daytime activity (Hastings 2006). In this study we investigated the impact of age and HF on activity, since both may reduce activity, and consequently affect subjective sleepiness. Methods: Measures of sleep and activity were made in 3 groups; 25 HF patients with SDB (HF-SDB), 22 HF with no SDB (HF-noSDB) and 10 age matched healthy controls. SDB was measured using polysomnography and defined as an apnea hypopnoea index (AHI) >10/hour. Patients were classified as obstructive or central SDB based on the majority (>50%) of events. Activity was measured with wrist actigraphy for 14 days in 1 minute epochs Statistical analysis was carried out using the Kruskal-Wallis test, and Mann-Whitney U test with Bonferroni . adjustment. Results: Median (IQR) age was 68 (59-73) years; HF-SDB 70 (63-75), HF-noSDB 62 (54-70), controls 66 (64-69) years (p=0.845). 90% of participants were male. Left ventricular ejection fraction in the HF-SDB and HF-noSDB groups was 31% (19-40) and 35% (28-42) respectively. The AHI in the HF-SDB, HF-noSDB and control groups was 20.6 (13.5-38.0), 3.7 (2.5-5.9) and 2.2 (1.4-4.3) events/hour respectively. 18 of the 25 HF-SDB group had predominantly central sleep apnea. Body mass index did not differ between groups. Epworth sleepiness score was neither elevated nor significantly different between the HF-SDB group and the HF-no SDB group (8 (6-12) vs (7 (5-10) p=0.275); but was higher in the HF-noSDB than in the control group (7 (5-10) vs 4 (3-7) p=0.006). Further results are shown in the table. Table 1: Sleep, activity and diary results . Values given are median and IQR. NPSG-nocturnal polysomnography; TIB-time in bed; NS-not significant.
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