Changes and clinical significance of heart rate turbulence in elderly patients with essential hypertension accompanied by type 2 diabetes mellitus

Objective To investigate the variations and clinical significance of heart rate turbulence(HRT) parameters in elderly patients with essential hypertension(EH) combined with type 2 diabetes mellitus(T2DM).Methods The turbulence onset(T0),turbulence slope(TS),turbulence timing(TT),turbulence dynamics(TD) and standard deviation of the NN interval(SDNN) were measured in 133 elderly patients with EH combined with T2DM(EH+T2DM group),141 elderly patients with EH only(EH group),130 elderly patients with T2DM only(T2DM group),140 senile healthy controls(senile control group) and 139 youth healthy controls(young control group) by the Space Lab software using 24 hour dynamic electrocardiogram(Holter) records.Correlations of T0,TS,TT and TD with age,mean heart rate,SDNN were analyzed.Results Compared with young control group,TO and TT were increased(all P0.01),but TS,TD and SDNN decreased significantly in senile control group(all P0.05).Compared with EH group and T2DM group,TO was enhanced but TS,TD and SDNN reduced obviously in EH+T2DM group(all P0.05).Compared with senile control group,TO was increased but TS,TD and SDNN decreased obviously in EH+T2DM group(all P0.01).Compared with senile control group,TO was raised up but TS,TD and SDNN cut down obviously in EH group and T2DM group(all P0.05).TO,TS,TD and SDNN had no change between EH group and T2DM group(all P0.05).TT had no alteration among 4 groups of the old people(all P0.05).Conclusions HRT is significantly attenuated in old patients with EH and T2DM only or EH accompanied by T2DM,suggesting the autonomic nerve function of elderly patients with EH and T2DM only or EH accompanied by T2DM be severely damaged but the impairment of autonomic nerve function in elderly patients with EH accompanied by T2DM be the best noticeable.