The clinical significance of detection to heart rate deceleration capacity and heart rate variability in patients with chronic heart failure

Objective: To study the change of heart rate deceleration capacity ( DC ) and heart rate variability in patients with chronic heart failure (CHF) and its relationship with left ventricular ejection fraction (LVEF). Methods: DC, LVEF, time and frequency domain parameters of HRV were measured in 66 patients with CHF and 34 healthy adults (control group) by using 24h Holter recordings and Echocardiography. The standard deviation of normal R-R intervals( SDNN), squares of differences between adjacent NN intervals ( RMSSD)，low frequency power( LFn ) and high frequency power( HFn ) and the changes of LVEF were compared between  the two groups，the relationship between DC，LVEF and HRV were studied in patients with CHF. Results: The median value of DC in the patients with CHF was significantly lower than that in control group( 3.1 ± 2.4 ms vs 7.2 ± 1.3 ms， P <0.01)．Incidence of abnormal DC in the CHF group was 57.5%，which was significantly higher than that in the control group ( P <0.01)．The HRV index, including SDNN、RMSSD、LFn、HFn, in the CHF group was significantly lower than that in normal control group ( P < 0.01). Significant positive correlation between HRV index and LVEF were confirmed ( P < 0.01). Conclusions: DC and HRV index are lower in patients with CHF and have a good correlation with the left ventricular ejection fraction.