Relationship between sleep apnoea and mortality in patients with ischaemic heart failure.
OBJECTIVE
To determine whether the influence of sleep apnoea (SA) on the risk of death differs in patients with ischaemic and in those with non-ischaemic heart failure (HF).


METHODS
Prospective observational study.


METHODS
Consecutive patients with HF with left ventricular ejection fraction < or =45% newly referred to the HF clinic between 1 September 1997 and 1 December 2004.


METHODS
Patients underwent sleep studies and were divided into those with moderate to severe SA (apnoea-hypopnoea index > or =15/h of sleep) and those with mild to no SA (apnoea-hypopnoea index <15/h of sleep). They were followed up for a mean of 32 months to determine all-cause mortality rate.


RESULTS
Of 193 patients, 34 (18%) died. In the ischaemic group, mortality risk adjusted for confounding factors was significantly higher in those with SA than in those without it (18.9 vs 4.6 deaths/100 patient-years, hazards ratio (HR) = 3.03, 95% CI 1.04 to 8.84, p = 0.043). In contrast, in the non-ischaemic HF group, there was no difference in adjusted mortality risk between those with, and those without, SA (3.9 vs 4.0 deaths/100 patient-years, p = 0.929).


CONCLUSIONS
In patients with HF, the presence of SA is independently associated with an increased risk of death in those with ischaemic, but not in those with non-ischaemic, aetiology. These findings suggest that patients with ischaemic cardiomyopathy are more susceptible to the adverse haemodynamic, autonomic and inflammatory consequences of SA than are those with non-ischaemic cardiomyopathy.
Yumino
D
D
Sleep Research Laboratory of Toronto Rehabilitation Institute, University of Toronto, Toronto, Ontario, Canada.
Wang
H
H
Floras
J S
JS
Newton
G E
GE
Mak
S
S
Ruttanaumpawan
P
P
Parker
J D
JD
Bradley
T D
TD
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002311:Cardiomyopathy, Dilated / Q000401:mortality; D002423:Cause of Death; D005260:Female; D006333:Heart Failure / Q000401:mortality*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000401:mortality*; D017286:Polysomnography; D011379:Prognosis; D011446:Prospective Studies; D018570:Risk Assessment; D012891:Sleep Apnea Syndromes / Q000401:mortality*; D018487:Ventricular Dysfunction, Left / Q000401:mortality