F. Tremel et al., High prevalence and persistence of sleep apnoea in patients referred for acute left ventricular failure and medically treated over 2 months, EUR HEART J, 20(16), 1999, pp. 1201-1209
Aims Cardiac failure patients were studied systematically using polysomnogr
aphy 1 month after recovering from acute pulmonary oedema, and again after
2 months of optimal medical treatment for cardiac failure.
Methods and Results This prospective study of consecutive patients was cond
ucted in a cardiac care unit of a university hospital. Vo(2) measurements a
nd left ventricular ejection fraction were recorded. Thirty-four patients,
initially recruited with pulmonary oedema, improved after 1 month of medica
l treatment to NYHA. II or III. They were aged less than 75 years and had a
left ventricular ejection fraction less than 45% at the time of inclusion.
Age was 62 (9) years, body mass index=27 (5) kg. m(-2) and an ejection fra
ction=30 (10)%. Eighteen of the 34 patients (53%) had coronary artery disea
se. Twenty-eight of the 34 had sleep apnoea syndrome with an apnoea+hypopno
ea index >15.h(-1) of sleep. Thus, the prevalence of sleep apnoea in this p
opulation was 82%. Twenty-one of 28 (75%) patients had central sleep apnoea
and seven of 28 (25%) had obstructive sleep apnoea. Patients with central
sleep apnoea had a lower Pace, than those with obstructive sleep apnoea (33
(5) vs 37 (5) mmHg, P<0.005). Significant correlations were found between
apnoea + hypopnoea index and peak exercise oxygen consumption (r= -0.73, P<
0.01), and apnoea+hypopnoea index and Paco(2), (r= -0.42, P=0.03). When onl
y central sleep apnoea patients were considered, a correlation between apno
ea+hypopnoea index and left ventricular ejection fraction was also demonstr
ated (r= - 0.46, P<0.04). After 2 months of optimal medical treatment only
two patients (both with central sleep apnoea) showed improvement (apnoea+hy
popnoea index <15.h(-1)).
Conclusions We have demonstrated a high prevalence of sleep apnoea, which p
ersisted after 2 months of medical treatment, in patients referred for acut
e left Ventricular failure. Central sleep apnoea can be considered a marker
of the severity of congestive heart failure.