Session 20 : Pharmacologie cardiovasculaire
INTEREST OF TIME DOMAIN MEASUREMENTS OF HEART PERIOD VARIABILITY IN RECURRENT MENTAL LOADS
L. Guedon-Moreau1. M. Kroumova1, E. Gyan1, C. Lefur2, JL Edme2, M. Romon2, C. Libersa1.
1 Clinical Investigation Center CH&U – INSERM, Hôpital Cardiologique 59037 Lille France; 2 Department of Nutrition CH&U 59037 Lille Cedex France
Spectral analysis of RR variability can be used to assess the effects of mental stress on sympathovagal balance. Time domain measurements of RR variability are usually used for long term ECG recordings. In this study, we evaluated the behavior of HR (mean heat rate), SD (standard deviation of RR ), rMSSD (square root of the mean of the sum of the squares of differences between adjacent RR intervals) and PNN50 (number of pairs of adjacent RR intervals differing by more than 50ms divided by the total number of all RR intervals) in 14 healthy subjects (mean age 25 years), undergoing recurrent mental loads. A spectral analysis of variability was also performed by calculating the total power, high frequency power (0.15-0.4 Hz) and low frequency power (0.04-0-15 Hz). Each subject participated in 2 sessions on separate days. 1: A control session without mental load. 2: a session with 5 ten minute-mental loads (one per hour), consisting in a computer task. A 12 hour ECG Holter recording was performed to assess RR intervals. RESULTS: Heart rate significantly increased during each mental load (p