Study On The Effect Of Age And Heart Failure In Heart Rate Variability And Diastolic Period Variability

Currently, cardiovascular disease (CVD) has become one of major threats to human health. Taking effective prevention and treatments has great social value and practical significance for improving human health and life quality. Electrocardiogram (ECG) signal and pulse wave(PW) signal which reflect the functional status of cardiovascular system contain a lot of useful physiological and biomedical information. Diagnosis technology based on heart rate variability (HRV) and heart diastolic period variability (DPV) analysis has become a hot study in biomedical engineering.This paper has done systematic study on the HRV, DPV and their coupling complexity, assessed the changes related with increasing age and heart failure respectively in HRV, DPV and their interactions, and explored new application in early diagnosis of CVD. The main work of this paper is described as follows.(1) This paper proposed a modified wavelet transform algorithm used for extraction of ECG characteristic points, then processed pulse wave with extracted information of R-waves. Firstly, we processed ECG with continuous wavelet transform, added coefficients of every level accordingly, and then detected R-waves with more accuracy. Secondly, we extracted start and end points of pulse wave with the algorithm based on physiological mechanism, which improved speed and instantaneity of the analysis system.(2) This paper explored the effects of aging on the cardiovascular system. The clinical trial and results of data analysis showed that:HRV variability decreased with increasing age and DPV behaved generally in the same way with HRV, which is consistent with the conclusion that HRV was expressed preferentially in DPV while the systolic period stayed relatively constant with a tiny variability. The short-range correlations of HRV and DPV decreased significantly with aging, which suggested that the interactions between HRV and DPV might provide additional valuable information for characterizing the autonomic regulation in aged individuals. (3) This paper explored the effects of heart failure on the cardiovascular system. We designed clinical trial on heart failure group and healthy control group with consistent age and the results showed that:there were significant differences in HRV between two groups, but with slightly differences in DPV, which suggested that HRV had effectiveness on the disease detection on heart failure group. Obvious differences existed in the correlations of HRV and DPV, both in short-range correlations and long-range correlations, which indicated that the coupling of HRV and DPV might provide potential valuable information for early detection of heart diseases. Statistical analysis showed that HRV and DPV long-range correlations had high specificity and sensitivity in heart failure detection.