The Synchronic Study Of Heart Rate Variability And Blood Pressure Variability In Patients Of Vessel Damage With Essential Hypertension

Background: In the past half century, essential hypertension (EH) has gradually beenthe number one killer of mankind, accounting for the largest proportion of the mortalityand morbidity of cardiovascular disease. As the major factor for cerebrovascular andcardiovascular diseases, hypertension can seriously affect the function of the heart, brainand kidney. Recent years with the deeper understanding of hypertension, we find thesympathetic nervous system plays an important pathophysiology role in EH. Autonomicnervous system exerts a direct effect on heart rate and vasoconstriction determining notonly blood pressure, blood pressure variability (BPV), blood pressure circadian rhythm, butalso affecting the heart rate variability (HRV). Studies have shown that chronicsympathetic activity can potentiate or aggravate target organ damage. Arteriosclerosis asthe pathological basis of many cardiovascular and cerebrovascular diseases shows its earlystep as decreasing of arterial elastic function which can accurately assess by pulse wavevelocity (PWV). PWV is an important method to detect early arteriosclerosis. This researchaims to investigate the relationship between sympathetic activity tested by synchronic HRVand BPV and vessel damage in patients with essential hypertension (EH).Methods: The275patients with EH admitted to cardiovascular ward in the FirstAffiliated Hospital of Dalian Medical University from April2011to January2014, wereenrolled in this study. Acquisition history, general information and biochemicalexamination of patients were collected. Meanwhile synchronic24h ambulatory blood pressuremonitoring (ABPM) and dynamic electrocardiogram (Holter) were performed for allparticipants. The HRV were detected by Holter including SDNN (standard deviation of all normal-to-normal intervals), SDANN (standard deviation of the average of allnormal-to-normal intervals in all5-minute intervals), rMSSD（root mean square ofdifferences between adjacent normal-to-normal intervals), pNN50(percent of NN50in thetotal number of normal to normal intervals）, CV (coefficient of variation)，VLF (very lowfrequency), LF (low frequency), HF (high frequency) and LF/HF. And indexes of systolicblood pressure (SBP), diastolic blood pressure (DBP), pulse pressure (PP), heart rate (HR),systolic blood pressure fall (SBPF), night/day heart rate ratio (n/d HR) and BPV weredetected by ABPM. The stiffness of the arterial is detected by carotid-femoral pulse wavevelocity (PWV). Subjects were divided into normal PWV group (PWV<9m/s) and highPWV group (PWV≥9m/s) according to PWV values. SPSS19.0statistical software forprocessing and analyzing the data, Multiple linear regression analysis was used to find theindependent factors of PWV.Results:1. Gender, Smoking, BMI, GLU, TC, TG, HDL-C, LDL-C, CRE, UA between the twogroups show no difference; But the clinical significance present on analyzing age andcourse of hypertension (P<0.01). PWV is positively correlated with age (P<0.05).2.24hSBP, dSBP, nSBP,24hPP, dPP, nPP,24hSSD, dSSD, nSSD in high PWV group aresignificantly higher than normal PWV group (P<0.01). SBPF in high PWV group aresignificantly lower than normal PWV group (P<0.01). Meanwhile the detection rate ofnon-dippers in high PWV group is higher than normal PWV group (P<0.01). PWV ispositively correlated with24hSBP, dSBP, nSBP,24hPP, dPP, nPP,24hSSD, dSSD,nSSD (P<0.01); PWV is significantly negatively correlated with SBPF(P<0.01).3. SDANN significantly decreased and LF, HF, LF/HF increased in high PWV group，andthere were statistical significance(P<0.05).The LF, HF are significantly positivelycorrelated with PWV (P<0.01), so are LF/HF (P<0.05).4. Night/day heart rate ratio in high PWV group are significantly higher than normalPWV group (P<0.01)，and is positively correlated with PWV (P<0.05). Moreover theNight/day heart rate ratio is independently associated to the arterial stiffness.5. Multiple linear regression analysis showed that PWV is independently correlated with24hPP,24hSSD, night/day heart rate ratio, LF, LF/HF, in which24hSSD, LF has thestrongest correlation. Conclusions:1. The synchronic study of heart rate variability and blood pressure variability, foundHRV decreased, BPV elevated in high PWV group.24hSSD, LF has the strongestindependently correlation with PWV. Autonomic nervous system dysfunction (LF/HF)and sympathetic nervous system activity (LF) are independent risk factors in theoccurrence and development of vascular damage in patients with EH. In whichsympathetic nervous system activity has the strongest influence in the development ofarterial stiffness.2. Night/day heart rate ratio is independently associated to the arterial stiffness. It is theeasiest way to reflect the status of the autonomic nervous system balance and isexpected to become a new sensitive indicator in clinical study for assessing the statusof the autonomic nervous system and forecasting the vascular damage in patients withEH.