Heart rate turbulence in patients with metabolic syndrome.

ABSTRACT

BACKGROUND: Metabolic syndrome is a cluster of risk factors leading to cardiometabolic diseases. The association between metabolic syndrome and cardiovascular disease (CVD) has been evaluated previously, but none of those studies looked at cardiac autonomic functions in these patients. The aim of the present study was to investigate the effect of metabolic syndrome on heart rate turbulence, which plays an important role in the development of CVD. METHODS: Thirty-seven patients (17 females and 20 males) were included in the metabolic syndrome group and 37 subjects (19 females and 18 males) were included in the control group. Heart rate turbulence (HRT) indices [turbulence onset (TO) and turbulence slope (TS)] were calculated from 24-hr ambulatory electocardiographic recordings. RESULTS: At least one of the TO or TS values were within the abnormal range in 62% of the patients within the metabolic syndrome group. In the control group, at least one of the TO or TS values were within the abnormal range in 27% of the subjects. CONCLUSIONS: Our study results indicate that cardiac autonomic function is impaired even in the absence of overt cardiac disease in patients with metabolic syndrome. Further studies are needed to elucidate the prognostic significance and clinical implications of impaired autonomic functions in patients with metabolic syndrome.