[Sleep disorders with nocturnal bradycardia in 2 depressed patients]

Polygraphic sleep exploration is usually not necessary to evaluate and treat such dyssomnias as nightmares or anguish dreams, but it may be indispensable in case of severe repeated or refractory sleep disorders, particularly in patients with concomitant depression. Two cases of major depression (DSM III R) associated with wakings during the night and dreams of death are reported. In both cases, polygraphic sleep exploration performed after complete, two-weeks long discontinuation of medicines revealed sinus bradycardia during paradoxical sleep, particularly in pre-waking periods. Heart rates ranged from 33 to 43 beats/minute in the most pronounced bradycardic episodes. The possibility of organic cardiac pathology was excluded by additional examinations. Atropine (175 mg) administered alone resulted in complete disappearance of bradycardic episodes and in improvement of objective and subjective sleep parameters. In these two cases bradycardia seemed to be due to vagal dysfunction with exaggeration of the "rebound" bradycardia which follows the initial tachycardia that occurs during the phasic phenomena of paradoxical sleep.