The continuum between daytime and nighttime disordered breathing in patients with heart failure

Background Disordered breathing (DB) patterns are frequent in patients with heart failure (HF) during both night- (NDB) and day-time (DDB). Few studies have analyzed their association.

Aims and Objectives To address in a large series the relationship between DDB and presence and severity of NDB.

Methods We studied 339 moderate-to-severe HF patients (age 59±9 yrs, NYHA 2.7±0.5, LVEF 33±10%) who underwent a 10-min daytime supine respiratory recording and polysomnography on the same or subsequent night.

Results DDB was observed in 157/339 (46%) patients while NDB (AHI›15/h) in 191 (55%). While total sleep time (TST) did not differ (351±71 vs 353±67 min), DDB patients had a higher percentage of TST in N1 (18±9 vs 16±8%, p=.047) and a lower percentage of TST in N3 (13±8 vs 15±8%, p=.043) as compared to non-DDB patients. Analysing the burden of NDB, DDB patients showed a higher AHI (25±17 vs 19±16/h, p=.0005) that was exclusively due to a higher frequency of central events (17±14 vs 12±12/h, p=.0002). Severe sleep apnea (AHI›30/h) was more frequent in patients with DDB (38 vs 18%, p=.007) who also had a higher ODI (30±18 vs 24±16/h, p=.0013), a lower min SaO2 (82±6 vs 84±5%, p=.0005) and a higher T90 (46±68 vs 31±63 min, p=.04). The difference in NDB burden between patients with and without DDB was not dependent on the supine dependency during the night.

Conclusions DDB are associated with the burden of NDB of central origin. These data support the hypothesis that, in HF, a continuum does exist between NDB and DDB and that the mechanisms operating at night also mediate the development of DB at daytime.