ECG ACTIVITY IN THE SLEEP OF INSOMNIAC PATIENTS UNDER THE INFLUENCE OF LORMETAZEPAM AND ZOPICLONE

The influence of the benzodiazepine hypnotic lormetazepam (1 mg) and t he cyclopyrrolone hypnotic zopiclone (7.5 mg) on heart rate activity w as studied in 16 elderly insomniacs in a placebo-controlled, randomise d, 3-fold crossover trial. After digital preprocessing of the EGG, QRS complexes were automatically recognised by a detection technique base d on adaptative thresholds. Both R-R periodicity and heart rate variab ility were analysed as a function of sleep stages and time of night. U nder placebo, heart rate decreased significantly from the first to the second half of the night. The relationship between sleep stages and h eart rate remained constant under both hypnotics. Although the two sub stances significantly modified the distribution of sleep stages, no re levant changes in ECG activity were observed when the proportion of th e different sleep stages was taken into consideration.