In this study, we investigated the influences of age and diabetes duration on cardiac beat-to-beat variation(BBV). BBV was performed in 47 NIDDM patients and 25 age-matched control subjects. The results were as follows:
1) There was no significant difference in BBV between control subjects (Group Ⅰ, 8.2±0.8 beat/min, mean±SEM) and NIDDM partients without neuropathic symptoms (Group Ⅱ-1, 7.3±0.8 beat/min), however, BBV of patients with neuropathic symptoms (Group Ⅱ-2, 4.4±0.4 beat/min) were significantly lower than others.
2) The relationship between BBV and age showed negative correlation in group Ⅰ (r=-0.551, p<0.05) and group Ⅱ-2 (r=-0.500, p<0.05), however, not in group Ⅱ-1 (r=-0.440, p=0.088).
3) The relationship between BBV and diabetes duration showed negative correlation in group Ⅱ-2 (r=-0.477, p<0.05).
4) In group Ⅱ-2, BBV of diabetic patients with duration of over 5 years (3.9±0.6 beat/min) was significantly lower thatn that of less than 5 years (6.5±0.3 neat/min) despite the same mean age.
These results suggest that in the evaluation of diabetic neurorathy by BBV, a consideration should be given to Patient´s age and diabetes duration.
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