Assesment of Autonomic Function in Metabolic Syndrome using Combination Heart Rate Variability and Heart Rate Turbulence

Background and objective: Metabolic syndrome (MetS) is described as a group of various abnormal metabolic risk factors such as obesity, dyslipidemia, increased blood pressure, increased plasma glucose levels, prothrombotic condition and proinflammatory state. These parameters are related to decreased parasympathetic and increased sympathetic activity. We aimed to evaluate autonomic function using a combination with  heart rate variability (HRV) and  heart rate turbulence (HRT) in metabolic syndrome to compare non-metabolic syndrome(non-MetS). Methods: We selected consecutive 50 patients with MetS and 50 patients with healthy non-MetS individuals. All patients underwent 24 hours holter monitoring to evaluate HRT and HRV parameters. Results: Age of patients was not different in two groups. Mean age of MetS patients was 57,50±12,13 and 54,6±10,25 in non- MetS individuals. Sex of patients was non different in MetS compared to non-MetS (37 female and 13 male vs. 22 female, 28 male p<0,05 respectively). SDNN and RMSSD was lower in MetS compared to those without MetS (131,96±49,12  vs  179,59±85,83 p=0,03 and 78,64±35,22 vs 112,73±81,24 p=0,08 respectively). SDANN, pNN50,Mean RR, mean heart rate, count of ventricular premature complex(VPC) were not different between two groups. Turbulence Slope(TS)  was not different in two groups. Turbulence Onset(TO)  was higher in MetS compared to non-MetS (2,01±15,29 and -6,21±13,5 p=0,005). Conclusion: We showed that autonomic function in MetS was impaired using a combination with HRT and HRV. These patients should be followed closely for adverse cardiovascular outcome especially including cardiac arrhythmia. Keywords: Metabolic syndrome, autonomic dysfunction, heart rate variability, heart rate turbulence