Heart Rate Turbulence And Clinical Prognosis In Chronic Heart Failure

Despite recent advances in the management of chronic heartfailure, mortality remains high. So identifying patients at high risk ofdeath is important. Recently, Schmidt reported the use of a newprognostic marker heart rate turbulence (HRT). It is assessed by 2parameters (turbulence onset and slope) derived from analyzing thefluctuation of RR intervals after a single ventricular premature beat(VPB). The turbulence onset indicates an overshoot decrease in theRR interval just after a VPB pause, and the turbulence slope indicateshow fast the RR interval changes after the pause. However, theunderlying mechanisms of the HRT are not yet understood. HRT isreported to predict the prognosis after myocardial infarction (MI), butits prognostic value in patients with CHF remains unknown. Thepurpose of the present study was to evaluate the prognosticsignificance of HRT in chronic heart failure (CHF) patients ascompared with other prognostic markers such as pump function andheart rate variability (HRV). In addition, it is well recognized that theincidence of sudden cardiac death (SCD) because of fatal ventriculartachycardia (VT) is considerably high in CHF patients,so we alsotested whether HRT is a marker for VT in CHF patients as comparedwith other markers including QT dispersion (QTd),HRV,LVEF. HRT was measured in 41 CHF patients and 20 patients withoutobvious heart diseases (control). HRT slope and HRT onset weremeasured by the original definitions using digitized Holter ECGrecordings. Cardiac pump function was assessed by echocardiography.The value of the HRT slope was significantly lower in CHF than incontrol (3.27±2.11vs 4.23±1.96;P<0.05). The value of the HRT onsetin patients with CHF was significantly higher than that in controlpatients (-0.96±2.03 vs -1.57±1.89;P<0.05). The HRT slope and onsetin CHF patients with VT were nearly identical to those without VT.The HRT slope appears to be a powerful prognostic marker that showssignificant differences between CHF subgroups when divided byclinical events;that is, CHF death and CHF hospitalization. However,it has limited value for predicting fatal ventricular arrhythmias. As tothe correlations between HRT, LVEF, and HRV in the CHF patients.The HRT slope was significantly correlated with the LVEF (P<0.05),SDNN (P<0.01), and HF (P<0.01), and the HRT onset wassignificantly correlated with SDNN, HF (P<0.05), but not with LVEF.Single Cox-regression analysis revealed that TO and TS, LVEF, TS,TO were the statistically significant predictors of CHF death.Multivariate Cox-regression analysis revealed that TO and TS was astronger predictors of CHF death than LVEF. The hazard ratio of theTS ≤2.5 and TO≥0 was 3.022 (95% confidence interval 1.20-6.33;P<0.01) and the hazard ratio of EF <30% was 2.482 (95%CI1.91-4.03).We got the conclusions as followed: The present study stronglysuggests that HRT is a powerful prognostic marker and should be atechniques for the assessmrnt of autonomic tone in patients with CHF.However the HRT slope and onset in CHF patients with VT werenearly identical to those without VT.