Inverse Relationship of Subjective Daytime Sleepiness to Sympathetic Activity in Heart Failure Patients with Obstructive Sleep Apnea
Montemurro LT et al. – In patients with heart failure (HF) and obstructive sleep apnea (OSA), the degree of subjective daytime sleepiness is inversely related to muscle SNA (MSNA). This relationship is likely mediated via central adrenergic alerting mechanisms. These findings help to explain the previously reported lack of daytime hypersomnolence in patients with HF and OSA.Methods
- Daytime muscle SNA (MSNA) was recorded in HF patients with OSA.
- Subjective daytime sleepiness was assessed by the Epworth Sleepiness Scale (ESS).
- The authors studied 27 patients with HF and OSA and divided them into two groups based on the median ESS score: a less sleepy group with an ESS score <6 (n=13) and a sleepier group with an ESS score ≥6 (n=14).
- The less sleepy group had higher MSNA (82.5±9.9 vs 69.3±18.6 bursts per 100 cardiac cycles, p=0.037) and a longer sleep onset latency (33±29 vs 14±13 minutes, p=0.039) than the sleepier group.
- The ESS score was inversely related to MSNA (r = –0.63, p<0.001), but not to the AHI, arousal index or indices of oxygen desaturation.