SHORT-TERM FREQUENCY AND TIME-DOMAIN ANALYSIS OF HEART-RATE-VARIABILITY IN TYPE-I DIABETIC SUBJECTS

Assessment of heart rate variability as a measure of sympathovagal bal ance has proven useful in the risk stratification of patients with cor onary artery disease. Since diabetic subjects with autonomic neuropath y, carrying a high risk of cardiovascular events, have been shown to h ave reduced heart rate variability, we performed a short-term (600 RR- intervals) frequency and time domain analysis in type I diabetic subje cts. 19 patients without clinical signs of autonomic neuropathy were c ompared with 11 age- and sex-matched control persons. At a comparable cycle length, diabetic subjects differed significantly from healthy co ntrols in all calculated time domain parameters (standard deviation: 4 1 +/- 23 vs. 66 +/- 17 ms, p = 0.005; root mean square successive diff erence of normal RR-intervals: 25 +/- 17 vs. 41 +/- 17 ms, p = 0.02) a nd frequency domain parameters (low frequency: 58 +/- 67 vs. 158 +/- 9 7 ms(2), p = 0.002; high frequency: 29 +/- 42 vs. 85 +/- 96 ms(2), p = 0.03). Thus, short-term frequency and time domain analysis of heart r ate variability can be used easily and quickly in an outpatient settin g for estimation of changes in the sympathovagal balance in diabetic s ubjects. However, the prognostic significance and the influence of dru gs on impaired heart rate variability in diabetic subjects have yet to be determined.