| Objective To investigate the change of heart rate turbulence(HRT)including turbulence timing(TT),turbulence onset (TO) and turbulence slope (TS) and its correlation with age, heart rate(HR) before ventricular premature complexes(VPCs), coupling interval, compensatory pause, and time domain heart rate variability (HRV) in patients with chronic heart failure(CHF).Methods A total of 82 patients with chronic heart failure (CHF group) and 89 patients without organic heart disease (control group) were assigned. TO, TS, TT, HR before VPCs, coupling interval, compensatory pause, SDNN, SDANN, SDNNINX, RMSSD and PNN50 were determined by 24h ambulatory electrocardiograph (Holter). TO, TS and TT were dichotomized at predefined cutpoints(TO≥0%; TS≤2.5ms/RRI; TT≥9). HRT was classified into the following 3 categories:HRT0(both TO and TS were normal), HRT1 (either TO or TS was abnormal) and HRT2(both TO and TS were abnormal). The value of above indexes was compared between two groups. The correlation of HRT with other indexes was analyzed.Results 1. There was no difference in age and gender percentage between two groups(P>0.05). Compared with the control group, the levels of TO and TT were significantly higher in CHF group while the level of TS was significantly lower in CHF group (P<0.05).2. The positive rate of TO and TS in CHF group was significantly higher than that in control group(P<0.05).3. The proportion of HRTO in CHF group was significantly lower than that in control group(P<0.05). The proportion of HRT2 in CHF group was significantly higher than that in control group (P<0.05).4. In both two groups,TS was negatively correlated with HR before VPCs, and was positively correlated with compensatory pause and HRV(P <0.05); TO was negatively correlated with HRV(P<0.05); TT was not correlated with all the other indexes(P>0.05). In control group, TO was positively correlated with age and TS was negative correlated with age(P <0.05). In CHF group, there was negatively correlation between TS and coupling interval (P<0.05).Conclusion 1.HRT appears significantly blunted in patients with CHF, The levels of TO and TT are higher and TS is lower in patients with CHF than those in control patients.2. TO and TS are influenced by HR before VPCs, age, coupling interval and compensatory pause. In clinical use of TO and TS, these factors should be considered.3. There was a close correlation between TO, TS and HRV, which suggests TO and TS are mainly assosciated with the cardiac autonomic nerve’s activity.4. TT was not correlated with all the other indexes. TT may be a more independent and objective index for predicting for high-risk patients Objective This study was designed to investigate the correlation of heart rate turbulence(HRT)including turbulence timing(TT), turbulence onset (TO) and turbulence slope (TS) to the severity of heart failure. In the meantime, we also explored the significance of heart rate turbulence as a predictor of mortality in patients with chronic heart failure (CHF).Methods A total of 82 patients with CHF were chosen. According to NYHA heart functional class(II, III, IV), they were classified into mild CHF group (NYHA II) and moderate-to-severe CHF group (NYHA III,Ⅳ). The 24h ambulatory electrocardiograph (Holter) record of each sample was processed.TO, TS and TT were determined. TO, TS and TT were dichotomized at predefined cutpoints(TO≥0; TS≤2.5ms/RRI; TT≥9).HRT was classified into the following 3 categories:HRT0(both TO and TS were normal); HRT1 (either TO or TS was abnormal) and HRT2 (both TO and TS were abnormal). Meanwhile, these indexes were recorded including the coupling interval and compensatory pause of ventricular premature complexes(VPCs), the heart rate(HR) before VPCs, SDNN, SDANN, SDNNINX, RMSSD, PNN50 and so on. Left ventricular ejection fraction(LVEF)and left ventricular end-diastolic diameter(LVEDD)were measured by ultrasonic cardiography. The B-type natriurctic peptide(BNP)level was measured. All patients were followed up and the primary end point was all-cause mortality. High risk factors were defined according to breakpoints previously used for risk stratification.Results 1. Compared with the mild CHF group, the value of TO was significantly higher while the value of TS was significantly lower in moderate-to-severe CHF group(P<0.05). The positive rate of TO and TS in moderate-to-severe CHF group was significantly higher than that in mild CHF group (P<0.05).2. The proportion of HRTO in moderate-to-severe CHF group was significantly lower than that in mild CHF group while the proportion of HRT2 in moderate-to-severe CHF group was significantly higher than that in mild CHF group(P<0.05).3. TS was negatively correlated with BNP and NYHA heart functional class, and was positively correlated with LVEF(P<0.05); TO was negatively correlated with LVEF, and was positively correlated with BNP and NYHA heart functional class(P<0.05); TT was not correlated with BNP, LVEF, LVEDD or NYHA heart functional class (P>0.05).4. During follow up(37.5±20.7)months,8 patients were lost to follow-up.26 among 74 patients died for all cause. The value of TT, BNP and HR was higher in patients who died than that in those who survived, however, the value of TS, LVEF and HRV was lower in patients who died than that in those who survived(P<0.05). On univariate analysis,6 variables were significantly associated with the primary end point, HRT2 was the strongest predictor, the second strongest was SDNN, the other significant predictors were TT, HR, TS and BNP(P<0.05). On multivariate analysis, HRT2, TT and SDNN were the most significant predictors of death after adjustment for HR. The hazard ratio subsequently were 9.203(P=0.003),7.684(P= 0.001) and 7.509(P=0.003).Conclusion 1.T0 and TS can reflect the left ventricular function and the severity of heart failure.2. HRT2 is very useful for death risk prediction in patients with CHF, it is a predictor better than other traditional factors.3. TT is independent on other traditional factors, may become a new and independent predictor of high-risk patients with CHF. |
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