| Objective:In order to analysis the possibility of using JJ interval to achieve the heart rate variability in the patients with chronic heart failure(CHF) using the self-developed Ballistocardiogram(BCG) equipment which can collected the signals of BCG and Electrocardiography(ECG); In order to evaluate the predictive value of RJ interval based on the BCG equipment in judging the clinic prognosis through the analysis of the clinical data in patients with chronic CHF; In order to explore the possibility of using RJ interval as a method in the procedure of resynchronization by analysis the RJ intervals under the four conditions after accepting the cardiac resynchronization therapy(CRT) in patients with CHF.Methods:1. A total of 21 patients with CHF were consecutive enrolled in our study(including 10 males and 11 females, and the age ranged from 58-75 years old). The signals of BCG and ECG of 21 patients were collected synchronously. It was used JJ intervals of BCG and RR intervals of ECG to calculate the cardiac periods of these two methods separately. The parameters of HRV analysis were calculated in time domain analysis, frequency domain analysis and nonlinear analysis. The results calculated from BCG were analyzed and tested with those calculated from the ECG using paired t-test statistically.2. A total of 98 patients with CHF were consecutive enrolled in our study(including 44 males and 54 females, and the age ranged from 58-75 years old). The signals of BCG and ECG of 98 patients were collected synchronously. The RJ interval was calculated from the J peak of the BCG waveforms to the R peak of the ECG waveforms in the same cardiac cycle and it was accepted the average RJ interval as the individual RJ interval value which was calculated from all intervals in 5 minutes. The clinical baseline data of all selected cases were recoded including age, gender, height, weight, the cause of CHF, the stage of CHF, the NYHA classification, the number of re-hospitalization, course of disease, heart rate, blood pressure, the data of biochemical examination, ECG parameters and Ultrasonicardiography(UCG) parameters. The end point of cardiac events, including death, re-hospitalization and accepting the resynchronization therapy, were assessed at the end of 3rd month after the patients were discharged from hospital. All patients were divided into low RJ interval group and high RJ interval group according to the result of RJ interval. The clinical baseline data and related inspective data were compared between the two groups. It was then analyzed using the single variable and multi variable Logistic regression according to the clinical events after the two groups were discharged from the hospital.3. A total of 15 patients with CHF were consecutive enrolled in our study(including 9 males and 6 females, and the age ranged from 48-80 years old). All patients had accepted CRT already. All patients received four times of the BCG measurement under the four conditions of CRT on(BIV), left ventricular(LV), right ventricular(RV) and no pacing in a random and blinded manner. The RJ interval was calculated from the J peak of the BCG waveforms to the R peak of the ECG waveforms in the same cardiac cycle and it was accepted the average RJ interval as the individual RJ interval value which was calculated from all intervals in 5 minutes under each condition of CRT. The four groups of RJ intervals calculated from the BCG measurement under the four different states of CRT were then compared using the analysis of variance.Results:1. The parameters of HRV analysis calculated from the methods using JJ intervals of BCG and RR intervals of ECG separately had high similarity. The correlation coefficients of SDNN, TP, LF, HF and SD2 between the BCG and ECG methods were high(r =1). The correlation coefficients of rMSSD and SD2 were 0.99 and they were 0.98 of PNN50 and LF/HF between the two methods. There were no significant differences between the two HRV analysis results(P>0.05).2. The clinical characteristics of high RJ interval group compared with low RJ interval group were older age longer course of illness. The character of ECG of high RJ interval groups compared with the low group were longer PR interval. The high group also had a worsen condition including the enlarging of left ventricular end diastolic dimension(LVEDD) and decreasing of left ventricular ejection fraction(LVEF). The major adverse clinical events occurred among 28 patients and was greater frequent among patients with high RJ interval compared with those of low RJ interval(38.8% vs 18.4%, P =0.03). Multivariate Logistic regression analysis showed that high RJ interval was an independent risk factor to predict the possibility of the major adverse cardiac events(OR=0.398, 95%CI 0.107~0.961, P=0.04).3. There was a total statistical significance between the four groups of RJ intervals calculated from the four different working conditions of CRT. The results showed that the RJ intervals under the condition of CRT on(Biventricular), left ventricular(LV), right ventricular(RV) and no pacing in a random and blinded manner were shortened obviously compared with the RJ interval derived from the CRT off mode condition by further using the LSD method to compared the data between the two groups and the difference was statistically significant(P<0.05).Conclusion:1. It is feasible to analysis HRV using the JJ interval on the basis of BCG signal and the method of BCG can be adopted to achieve the analysis of HRV in patients with CHF.2. The prognosis of CHF patients with high RJ interval was poor because of the occurrence of the adverse cardiac events at least in a short term. RJ interval was a valuable factor for predicting the prognosis of patients with CHF and it is necessary to pay more attention to patients with high RJ interval.3. There is significant difference between the RJ intervals under the four conditions of pacemaker and there is a need for more depth research on RJ interval. Relatively speaking, this suggests that the RJ interval may be a more objective parameter during the CRT optimization. |
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