ACCEPTED (#VINI5133) Enhanced Frequency Domain Analysis Identifies Early Autonomic Dysfunction That May Lead To Elevated Blood Pressure In Diabetics

Background: Enhanced frequency domain (fd) analysis (EFDA) of heart rate variability (HRV) can differentiate ANS dysfunction before structural deficits present. Early ANS decline starts with the parasympathetics (PSNS) weakening, then the sympathetics (SNS). Our hypothesis is that before the SNS weakens it is strengthened by the initial PSNS weakness. This period of SNS excess might up regulate BP. Then when the SNS weakens, the ability to down regulate BP is lost. Methods: Two or more ANS tests were performed on 389 adult diabetic patients (ages 22 to 93). From these data, the patient’s EFDA (LFa and RFa) parameters and BP were measured at rest and in response to clinical challenges, including paced deep breathing (DB) and a series of short Valsalvas (V). The data are normalized to age 25. Results: The RFa (a parasympathetic measure) declines from ages 25 to 45, whereas the LFa (a sympathetic measure) decline starts at age 35 (see Figure). Meanwhile, the BP measurements both at rest and during the Valsalva challenge both increase sharply from age 25 to 35. The resting (baseline) BP then levels off (at 130 mmHg) but the Valsalva BP decreases until about 45 before it levels off (at 110 mmHg). Conclusions: The parasympathetics seem to be more sensitive to the effects of diabetes at first. The initially, less susceptible sympathetics start declining 10 years later,on average. This decade of relative sympathetic excess is coincident with a significant increase in BP. After the sympathetics weaken, the Valsalva BP declines and remains lower than the resting BP. A further suggestion of weakness in the sympathetics