RESUMEN
BACKGROUND: Microalbuminuria (MAU) represents in patients with type 2 diabetes a risk factor for total and cardiovascular mortality and morbidity, whose principal pathogenic mechanism is the development of atherosclerosis. Other factors may also participate, e.g., cardiovascular vegetative neuropathy, which is supposed to be an independent risk factor. The aim of the study was the analysis of the cardiovascular autonomic regulations in patients with type 2 diabetes and microalbuminuria. METHODS AND RESULTS: 16 patients with type 2 diabetes and microalbuminuria and 23 healthy controls were included in the study. Heart rate variability was tested (during short-term recording at rest, deep breathing, orthostasis and Valsalva manoeuvre) and spectral analysis of telemetric records of heart rate in three positions (lying--standing--lying) was employed. In the group of patients with type 2 diabetes and MAU, in comparison with patients without MAU and controls, significant differences in heart rate variability during deep breathing were found. In comparison to controls, differences were found also during the Valsalve manoeuvre. In parameters of reaction of the heart rate to orthostasis, both groups of diabetic patients differed from controls. When comparing patients with MAU and controls significant differences were also found in spectral analysis of the heart rate variability, namely in total spectral power and the power of the low frequency band in both recumbent positions. In the same parameters, significant differences were found also between patients with and without MAU. The later were not different from the controls. CONCLUSIONS: The presented results indicate the existence of a significant impairment of the autonomic nervous system in patients with type 2 diabetes and microalbuminuria. This fact may contribute to the higher cardiovascular risk in this group of diabetic patients.