Continuous and non-invasive measurement of blood pressure (BP) is of great importance particularly for patients in critical state. To achieve continuous and cuffless BP monitoring, pulse transit time (PTT) has been reported as a potential parameter. Nevertheless, this approach remains very sensitive, cumbersome and disagreeable in ambulatory measurement. This paper proposes a new approach to estimate blood pressure through PCG signal by exploring the correlation between PTT and diastolic duration (S21). In this purpose, an artificial neural network was developed using as input data: (systolic duration, diastolic duration, heart rate, sex, height and weight). According to the NN decision, the mean blood pressure was measured and consequently the systolic and the diastolic pressures were estimated. The proposed method is evaluated on 37 subjects. The obtained results are satisfactory, where, the error in the estimation of the systolic and the diastolic pressures compared to the commercial blood pressure device was in the order of 6 .48 ± 4.48 mmHg and 3 .91 ± 2.58 mmHg, respectively, which are very close to the AAMI standard, 5 ± 8 mmHg. This shows the feasibility of estimating of blood pressure using PCG.
Blood Pressure ; Heart Rate ; Humans ; Methods ; Pulse Wave Analysis

Characteristics in pulse wave signals (PWSs) include the information of physiology and pathology of human cardiovascular system. Therefore, identification of characteristic points in PWSs plays a significant role in analyzing human cardiovascular system. Particularly, the characteristic points show personal dependent features and are easy to be affected. Acquiring a signal with high signal-to-noise ratio (SNR) and integrity is fundamentally important to precisely identify the characteristic points. Based on the mathematical morphology theory, we design a combined filter, which can effectively suppress the baseline drift and remove the high-frequency noise simultaneously, to preprocess the PWSs. Furthermore, the characteristic points of the preprocessed signal are extracted according to its position relations with the zero-crossing points of wavelet coefficients of the signal. In addition, the differential method is adopted to calibrate the position offset of characteristic points caused by the wavelet transform. We investigated four typical PWSs reconstructed by three Gaussian functions with tunable parameters. The numerical results suggested that the proposed method could identify the characteristic points of PWSs accurately.
Algorithms ; Heart Rate ; Humans ; Normal Distribution ; Pulse Wave Analysis ; methods ; Wavelet Analysis

BACKGROUND: Arterial stiffness is a strong indicator of cardiovascular risk. Increased visceral fat confers greater risks of metabolic syndrome and cardiovascular events. The aim of this study was to elucidate the relationships between arterial stiffness and regional distribution of abdominal adiposity (i.e. subcutaneous and visceral adipose tissue). METHODS: Thirty obese participants (M:F=17:13, mean age=53.6+/-12.0 years) underwent anthropometric measurements, laboratory procedures such as serum lipid levels and abdominal computed tomography scan. The aortofemoral pulse wave velocity was measured by foot to foot method using two continuous Doppler waves. RESULTS: Pulse wave velocity was positively associated with age, hip circumference (P<0.01), visceral to subcutaneous abdominal fat ratio and body weight (P<0.05), but independent of the total abdominal, visceral, and subcutanous fat. Although not positively associated, the mean pulse wave velocity tended to be higher in patients with history of hypertension or diabetes. CONCLUSIONS: The site of abdominal fat distribution contribute to the prediction of arterial stiffness and visceral adiposity is associated with increased risk of cardiovascular events.
Abdominal Fat ; Adiposity* ; Body Weight ; Foot ; Hip ; Humans ; Hypertension ; Intra-Abdominal Fat ; Methods ; Pulse Wave Analysis ; Vascular Stiffness*

In the process of hemodialysis, the patients' blood pressure and pulse wave are likely to change considerably so that hypotension and rapid heart rate may be dangerous to the hemodialysts' life. Based on the environment of hemodialysis room, we designed the communication system using SPCE061A single-chip computer and STC89C52 single-chip computer to realize wireless communication between upper system and the two single-chip computers, and on the upper computer the pulse wave can display at real-time and save data on the data base. At the same time we designed an interface program to reduce noise by way of frequency domain analysis and wavelet denoising. It can draw the cycle pulse wave, eigenvalue-K, the maximum peak and peak frequency, it can effectively judge a racing heart in the hemodialysis and can also evaluate vascular sclerosis of hemodialysis. In short, the system is able to improve treatment security and reduce the burden of the doctors and nurses in hemodialysis rooms.
Algorithms ; Humans ; Information Systems ; Monitoring, Physiologic ; methods ; Pulse Wave Analysis ; Radial Artery ; Renal Dialysis ; adverse effects ; Software Design

Neurofibromatosis type 1 is an autosomal dominant genetic disorder characterized by the presence of café au lait spots, axillary and inguinal freckling, Lisch nodules, and neurofibromas. Hypertension is a relatively frequent complication, usually caused by renal artery stenosis or pheochromocytomas. We describe the case of a 15-year-old boy with neurofibromatosis type 1 who was also diagnosed with resistant hypertension. Despite an extensive evaluation, the etiology of his hypertension remained indeterminate. Estimation of the brachial-ankle pulse wave velocity and ambulatory arterial stiffness index could validate the existence of arterial stiffness. Further, a combination of carvedilol and angiotension receptor blockers was administered, which successfully controlled his resistant hypertension. We propose that the estimation of the brachial-ankle pulse wave velocity measure and ambulatory arterial stiffness index is a noninvasive method, and these two parameters are relatively simple tools that can be used for the detection of arterial stiffness due to neurofibromatosis type 1-related vasculopathy.
Adolescent* ; Humans ; Hypertension* ; Male ; Methods ; Neurofibroma ; Neurofibromatoses* ; Neurofibromatosis 1* ; Pheochromocytoma ; Pulse Wave Analysis ; Renal Artery Obstruction ; Vascular Stiffness*

OBJECTIVES: To study the application of three-dimensional speckle-tracking imaging in evaluating left ventricular systolic function and its correlation with peripheral arterial elasticity in children with simple obesity. METHODS: Random sampling combined with convenience sampling was used to obtain research samples, and then the samples were divided into an obesity group (23 cases), an overweight group (21 cases), and a normal group (24 cases). Three-dimensional speckle-tracking imaging was used to measure the global longitudinal strain (GLS), global radial strain (GRS), and global circumferential strain (GCS) of the left ventricle. An automatic arteriosclerosis tester was used to measure ankle-brachial index (ABI) and brachial-ankle pulse wave velocity (baPWV). These parameters were compared among the three groups. The correlation of three-dimensional speckle-tracking parameters with ABI and baPWV was evaluated. RESULTS: There were no significant differences in GLS, GRS, and GCS between the obesity and normal groups (P>0.05). The overweight group had a significantly higher GLS than the normal group [(-24±7) vs (-19±12), P<0.05]. The obesity and overweight groups had a significantly lower ABI than the normal group [(1.00±0.09)/(1.09±0.13) vs (2.25±0.13), P<0.05). The obesity group had a significantly higher baPWV than the normal group [(978±109) vs (905±22), P<0.05]. In the children with obesity, GLS was positively correlated with baPWV (r=0.516, P<0.05) , but not correlated with ABI (P>0.05), and GCS and GRS had no significant correlation with ABI or baPWV (P>0.05). CONCLUSIONS There are varying degrees of changes in left ventricular systolic function and peripheral arterial elasticity in children with simple obesity, and there is a certain correlation between them.
Ankle Brachial Index ; Child ; Echocardiography, Three-Dimensional/methods* ; Elasticity ; Humans ; Obesity ; Overweight ; Prospective Studies ; Pulse Wave Analysis

The present paper aims to investigate the relation between characteristic parameters of transesophageal photoelectric pulse wave in descending aorta and ambulatory artery blood pressure. The chests of ten adult experimental dogs were performed to take the photoelectric pulse wave of descending aorta transesophageally. The concurrent femoral artery invasive blood pressure was recorded simultaneously. Stepwise regression analysis method was used to study the correlation efficient between characteristic parameters of descending aorta pulse wave (H, h, h/H, g/H, At, s, H(1 + ts/td), k)and invasive artery blood pressure. The characteristic parameters, k and h/H (ratio: 90% and 80%) was proved that they had good correlation with systolic pressure; and k, H and s (ratio: 90%, 80% and 70%), had good correlation with diastolic pressure; while k and H (ratio: 90% for both) had good correlation with mean pressure. The mean values of multiple correlation coefficients of the selected characteristic parameters of descending aorta pulse wave with systolic pressure, diastolic pressure and mean pressure of femoral artery were 0.871, 0.900 and 0.856, respectively. The characteristic parameters of descending aorta pulse wave had specific correlation with systolic pressure, diastolic pressure and mean pressure.
Animals ; Aorta, Thoracic ; physiology ; Blood Pressure ; physiology ; Blood Pressure Monitoring, Ambulatory ; methods ; Dogs ; Electrophysiologic Techniques, Cardiac ; methods ; Female ; Femoral Artery ; physiology ; Male ; Pulse Wave Analysis ; methods ; Regression Analysis

Transrectal Doppler sonography was used to evaluate uterine blood flow during the first two weeks after parturition in six primiparous Simmental cows. The uterine blood flow was evaluated on the day of parturition (Day 0), once daily from Days 1 to 8 and then every other day until Day 14. Blood flow was quantified by determining the diameter (D), the time-averaged maximum velocity (TAMV), the pulsatility index (PI) and the blood flow volume (BFV) of the uterine arteries ipsilateral and contralateral to the formerly pregnant uterine horn. During the first four days after calving D, TAMV and BFV declined (ipsilateral: TAMV 70%, BFV 87%, contralateral: D 47%, BFV 84%; p < 0.05), while PI increased (ipsilateral 158%, contralateral 100%; p < 0.05) distinctly. Between Days 4 and 14 only the ipsilateral D (12%) and the BFV of both arteries (ipsilateral 5%, contralateral 8%) decreased (p < 0.05). Blood flow variables were very strongly correlated with each other (r > +/-0.75, p < 0.05), with negative correlations with PI and positive correlations with all other investigated factors. Overall, this study revealed characteristic changes in uterine perfusion during the first two weeks after parturition in cows that were pronounced during the first four days postpartum.
Animals ; Blood Flow Velocity/veterinary ; Cattle ; Female ; Parturition ; *Postpartum Period ; Pulse Wave Analysis/veterinary ; Ultrasonography, Doppler, Color/*methods/veterinary ; Uterine Artery/anatomy & histology/*ultrasonography ; Uterus/*blood supply/*ultrasonography

OBJECTIVE: To utilized the baseline data of the Beijing Fangshan Family Cohort Study, and to estimate whether the association between a healthy lifestyle and arterial stiffness might be modified by genetic effects. METHODS: Probands and their relatives from 9 rural areas in Fangshan district, Beijing were included in this study. We developed a healthy lifestyle score based on five lifestyle behaviors: smoking, alcohol consumption, body mass index (BMI), dietary pattern, and physical activity. The measurements of arterial stiffness were brachial-ankle pulse wave velocity (baPWV) and ankle-brachial index (ABI). A variance component model was used to determine the heritability of arterial stiffness. Genotype-environment interaction effects were performed by the maximum likelihood methods. Subsequently, 45 candidate single nucleotide polymorphisms (SNPs) located in the glycolipid metabolism pathway were selected, and generalized estimated equations were used to assess the gene-environment interaction effects between particular genetic loci and healthy lifestyles. RESULTS: A total of 6 302 study subjects across 3 225 pedigrees were enrolled in this study, with a mean age of 56.9 years and 45.1% male. Heritability of baPWV and ABI was 0.360 (95%CI: 0.302-0.418) and 0.243 (95%CI: 0.175-0.311), respectively. Significant genotype-healthy diet interaction on baPWV and genotype-BMI interaction on ABI were observed. Following the findings of genotype-environment interaction analysis, we further identified two SNPs located in ADAMTS9-AS2 and CDH13 might modify the association between healthy dietary pattern and arterial stiffness, indicating that adherence to a healthy dietary pattern might attenuate the genetic risk on arterial stiffness. Three SNPs in CDKAL1, ATP8B2 and SLC30A8 were shown to interact with BMI, implying that maintaining BMI within a healthy range might decrease the genetic risk of arterial stiffness. CONCLUSION The current study discovered that genotype-healthy dietary pattern and genotype-BMI interactions might affect the risk of arterial stiffness. Furthermore, we identified five genetic loci that might modify the relationship between healthy dietary pattern and BMI with arterial stiffness. Our findings suggested that a healthy lifestyle may reduce the genetic risk of arterial stiffness. This study has laid the groundwork for future research exploring mechanisms of arterial stiffness.
Humans ; Male ; Middle Aged ; Female ; Ankle Brachial Index ; Cohort Studies ; Gene-Environment Interaction ; Vascular Stiffness/genetics* ; Pedigree ; Pulse Wave Analysis/methods* ; Genotype

PURPOSE: Despite technical simplicity and the low cost of brachial-ankle pulse wave velocity (BA-PWV), its use has been hampered by a lack of data supporting its usefulness and reliability. The aim of this study was to evaluate the usefulness of BA-PWV to measure aortic stiffness in comparison to using cardiovascular magnetic resonance (CMR). MATERIALS AND METHODS: A total of 124 participants without cardiovascular risk factors volunteered for this study. BA-PWV was measured using a vascular testing device. On the same day, using CMR, cross-sectional areas for distensibility and average blood flow were measured at four aortic levels: the ascending, upper thoracic descending, lower thoracic descending, and abdominal aorta. RESULTS: Compared to PWV measured by CMR, BA-PWV values were significantly higher and the differences therein were similar in all age groups (all p<0.001). There was a significant correlation between BA-PWV and PWV by CMR (r=0.697, p<0.001). Both BA-PWV and PWV by CMR were significantly and positively associated with age (r=0.652 and 0.724, p<0.001). The reciprocal of aortic distensibility also demonstrated a statistically significant positive correlation with BA-PWV (r=0.583 to 0.673, all p<0.001). CONCLUSION: BA-PWV was well correlated with central aortic PWV and distensibility, as measured by CMR, regardless of age and sex.
Adult ; Ankle Brachial Index/*methods ; Ankle Joint ; Aorta/anatomy & histology/*physiology ; *Blood Flow Velocity ; Cardiovascular Diseases ; Female ; Heart/physiopathology ; Humans ; *Magnetic Resonance Imaging, Cine ; Male ; Pulse Wave Analysis/*methods ; Regional Blood Flow ; Reproducibility of Results ; Risk Factors ; *Vascular Stiffness