AUTONOMIC IMBALANCE IN DIABETIC WOMEN
There is growing evidence for the role of the autonomic nervous system in the in a wide range of diseases.One of the most overlooked of all serious complications of diabetes is cardiovascular autonomic neuropathy (CAN), which encompasses damage to the autonomic nerve fibers that innervate the heart and blood vessels, resulting in abnormalities in heart rate control and vascular dynamics.Nonlinear dynamics parameter are proved to be related to heart rate variability and involved in the risk stratification for ventricular arrhythmias and sudden cardiac death.
Numerous studies highlight that diabetic women are more exposed to sudden cardiac death compared to men population.We have analyzed a study group of 40 women diabetic patients admitted in the Cardiology Clinic of the Emergency County Hospital Timisoara. The mean age of the study group was 59.5 years. Acute coronary syndrome has been associated to diabetes in 15 patients. Ventricular events defined by severe ectopic beats (R/T phenomena) or repetitive ventricular arrhythmic episodes (ie. ventricular tachycardia) were noticed in 21 patients. The main left ventricular ejection fraction was 41 % and the mean heart rate was 77 beats / min. The ECG signals have been recorded using a 24 h ECG Holter monitoring system from Labtech (Hungary), at 25 mm/s. All ECG signals were processed using Nevrokard Long-Term aHRV (LT-aHRV v 5.0.0) and Kubios HRV 2.0 software.
The mean of all RR intervals (NN), standard deviation of all normal-normal RR intervals (SDNN), the nonlinear dynamics parameters, as detrended fluctuation analysis short-term a1 (DFA a1), Poincaré plot analysis, and sample entropy analysis was performed for all ECG signals. From the Poincaré plot analysis, using Kubios HRV 2.0 software, we obtained automatically the values of the short-term scaling exponent.Spectral power was quantified by fast-Fourier transformation analysis (FFT 256 points, Welch) and by autoregressive method, model 20 in 2 frequency bands: low frequency (0.05 - 0.15 Hz) and high frequency (0.15 - 0.4 Hz). A high sympathetic activity (LF/HF: 1.7) and by altered short-term fractal scaling exponent alpha that is significantly lower in women with diabetes (0.64) compared with control group. The nonlinear dynamics parameters correlates significant with LF/HF ratio (r: 0.45) and with SDNN (r: 0.58). This study suggests that nonlinear analysis technique may complement traditional ECG analysis. The nonlinear dynamic methods could have clinical and prognostic applicability also in short-time ECG series.In our study women with diabetes, are patients with altered heart rate variability and with significant changes of the nonlinear dynamic parameters of heart rate.
All this aspects suggest ahigh vulnerability of this type of patients.