Abstract
We have experienced many diabetic patients in whom R-R interval variations appeared to be reversible, improving with control of the metabolic state. Case 1.59-year-old woman. She had shown a brittle-type variation in her blood glucose levels, which was stabilized by continuous subcutaneous insulin infusion. Her HbA1 decreased from 19.6% to 12.0%. At the same time, her RR interval variation improved from 37 to 72 msec. Case 2.52-year-old man. He was newly found to have diabetes mellitus, when his fasting blood glucose (FBG) was 478 mg/dl and his HbA1 was 16.0%. After diet therapy, these parameters were markedly improved (FBG 107 mg/dl, and HbA1 12.5%) and his R-R interval variation was increased from 244 to 339 msec.
To assess whether metabolic state affects R-R interval variations, 51 diabetic outpatients (22 males, 29 females, age 57±10) were studied. The FBG, HbA1 and R-R interval variations were measured twice at an interval of one month. There was no relationship between the changes in FBG and R-R interval variation. Two groups were selected from among the patients in this study: one showed more than a 10% decreasing rate of HbA1 (group A) and the other, more than a 10% increasing rate of HbA1 (group B) during the one-month observation period. The change in R-R interval variation of group A was 6±14% and that of group B was -20±23%(p<0.02). From these results, it is suggested that the R-R interval variation is affected by the metabolic state during 1-2 months.
