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).
Design: Prospective observational study.
Patients: Consecutive patients with HF with left ventricular ejection fraction ⩽45% newly referred to the HF clinic between 1 September 1997 and 1 December 2004.
Main outcome measures: Patients underwent sleep studies and were divided into those with moderate to severe SA (apnoea–hypopnoea index ⩾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.
Statistics from Altmetric.com
Funding: Supported by a programme grant PRG-5275 from the Heart and Stroke Foundation of Ontario. DY is supported by an unrestricted research fellowship from Respironics Inc, JSF by a Canada Research Chair in integrative cardiovascular biology and a Career Investigator Award from the Heart and Stroke Foundation of Ontario, HW was supported by research fellowships from the departments of medicine of the University of Toronto and Merck-Frosst, SM by a New Investigator Award from the Heart and Stroke Foundation of Ontario, PR by a research fellowship from Siriraj Hospital, Mahidol University, Bangkok, Thailand and JDP by a Career Investigator Award from the Heart and Stroke Foundation of Ontario.
Competing interests: None.
Ethics approval: Ethics committee approval from Mount Sinai Hospital and Toronto Rehabilitation Institute.
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.