HEART RATE RESPONSE AND HYPOCRETIN DEFICIENCY IN NARCOLEPSY
Attenuated Heart Rate Response is Associated with Hypocretin Deficiency in Patients with Narcolepsy
Gertrud Laura Sorensen, MScE1,2,3; Stine Knudsen, MD, PhD1; Eva Rosa Petersen, MD1; Jacob Kempfner, MScE1,2,3; Steen Gammeltoft, MD, Dr. Med Sci4; Helge Bjarup Dissing Sorensen, MScE, PhD4; Poul Jennum, MD, Dr. Med. Sci1,2
1Danish Center for Sleep Medicine, Glostrup University Hospital, Glostrup Hospital, Denmark; 2Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark; 3Department of Electrical Engineering, Technical University of Denmark, Kongens Lyngby, Denmark; 4Department of Diagnostics, Glostrup University Hospital, Denmark
Several studies have suggested that hypocretin-1 may influence the cerebral control of the cardiovascular system. We analyzed whether hypocretin-1 deficiency in narcolepsy patients may result in a reduced heart rate response.
We analyzed the heart rate response during various sleep stages from a 1-night polysomnography in patients with narcolepsy and healthy controls. The narcolepsy group was subdivided by the presence of +/− cataplexy and +/− hypocretin-1 deficiency.
Sleep laboratory studies conducted from 2001-2011.
In total 67 narcolepsy patients and 22 control subjects were included in the study. Cataplexy was present in 46 patients and hypocretin-1 deficiency in 38 patients.
Measurements and Results:
All patients with narcolepsy had a significantly reduced heart rate response associated with arousals and leg movements (P < 0.05). Heart rate response associated with arousals was significantly lower in the hypocretin-1 deficiency and cataplexy groups compared with patients with normal hypocretin-1 levels (P < 0.04) and patients without cataplexy (P < 0.04). Only hypocretin-1 deficiency significantly predicted the heart rate response associated with arousals in both REM and non-REM in a multivariate linear regression.
Our results show that autonomic dysfunction is part of the narcoleptic phenotype, and that hypocretin-1 deficiency is the primary predictor of this dysfunction. This finding suggests that the hypocretin system participates in the modulation of cardiovascular function at rest.
Sorensen GL; Knudsen S; Petersen ER; Kempfner J; Gammeltoft S; Sorensen HBD; Jennum P. Attenuated heart rate response is associated with hypocretin deficiency in patients with narcolepsy. SLEEP 2013;36(1):91–98.