Change of 24 Hours Heart Rate Variablity in Older Healthy Subjects and Older Hypertensive Patients

Kwak, Hyun Jin

Abstract

BACKGROUND
: Heart rate variability informed us to diagnose impairment of autonomic nervous system in patient with diabetes, hypertension, ischemic heart disease, chronic renal disease, arrhythmia. Change of autonomic nervous system is related to circadian rhythm, stress, physical activity, age and so on. Especially, impairment of vagal nervous system with age help us to expect sudden cardiac death, myocardial infarction, arrhythmia. So we survey heart rate variability by using 24 hours Holter monitoring to expect impairment of autonomic nervous system in elderly hypertensive patients.
METHODS
: In order to assess 24 hours heart rate variability, we used Del Mar Avionics 563 Holter monitoring on 15 older hypertensive patient (>or=65 years), 15 older hypertensive patient(<64 years), 15 younger healthy subjects (<64 years), and 15 older healthy subjects (>or=65 years). The following frequency domain variables were considered: low frequency(LF), high frequency(HF) power spectral parameter, and LF/HF ratio.
Results
: 1) There was significant decrease in LF power spectral parameter in older groups compared with younger groups 394.0+/-237.8 vs 127.7+/-96.3, p<0.05, 171.8+/-173.5 vs 40.8+/-33.8, p<0.05). 2) In hypertensive patients, there was significant decrease in HF power spectral parameter compared with healthy subjects(989.2+/-553.8 vs 526.0+/-364.7, p<0.05, 804.2+/-404.5 vs 368.8+/-241.2, p<0.05). 3) Although there was no significant difference, L/H ratio decreased in older groups compared with younger gourps. 4) In circadian rhythm, control subjects had low HF power spectral parameter at morning. LF/HF ratio was high at morning in younger groups.
CONCLUSION
: L/H ratio was depressed in older groups. HF was blunted in hypertensive groups. Thus, impairment of autonomic nervous system was accelerated by age and hypertension.