Volume Pulse Wave Research Articles

Age-Related Changes in Blood Volume Pulse Wave at Fingers and Ears.

The decline in vascular elasticity with aging can be manifested in the shape of pulse wave. The study investigated the pulse wave features that are sensitive to age and the pattern of these features change with increasing age were examined. Five features were proposed and extracted from the photoplethysmography (PPG)-based pulse wave or its first derivative wave. The correlation between these PPG features and ages was studied in 100 healthy subjects with a wide range of ages (20-71 years). Piecewise regression coefficients were calculated to examine the rates of change of the PPG features with age at different age stages. The proposed PPG features obtained from the finger showed a strong and significant correlation with age (with r = 0.76 - 0.77, p < 0.01), indicating higher sensitivity to age changes compared to the PPG features reported in previous studies (with r = 0.66 - 0.75). The correlation remained significant even after correcting for other clinical variables. The rate of change of the PPG feature values was found to be significantly faster in subjects aged ≥40 years compared to those aged < 40 years in the healthy population. This rate of change was similar to the age-related progression of arterial stiffness evaluated by pulse wave velocity (PWV), which is considered a gold standard for evaluating vascular stiffness. The proposed PPG features showed a high correlation with chronological age in healthy subjects and exhibited a similar age-related change trend as PWV. With the convenience of PPG measures, the proposed age-related features have the potential to be used as biomarkers for vascular aging and estimating the risk of cardiovascular disease.

The Investigation of Bio-impedance Analysis at a Wrist Phantom with Two Pulsatile Arteries.

Bio-impedance analysis (BIA) has been widely investigated for hemodynamic monitoring. However, previous works rarely modelled two synchronously pulsatile arteries (representing the radial and ulnar arteries) in the wrist/forearm model. This work aims to clarify and quantify the influences of two pulsatile arteries on BIA. First, two blood-filled arteries were structured in a 3D wrist segment using the finite element method (FEM). Afterwards, an easy-to-produce two-arteries artificial wrist was fabricated with two components: gelatine-based surrounding tissue phantom and saline blood phantom. A syringe driver was utilised to constrict the arteries, and the impedance signals were measured using a Multi-frequency Impedance Analyser (MFIA). Both simulation and experimental results demonstrated the non-negligible influences of the ulnar artery on the overall BIA, inducing unwanted resistance changes to the acquired signals from the radial artery. The phantom experiments revealed the summation of the individual resistance changes caused by a single pulsatile artery was approximately equal to the measured resistance change caused by two synchronously pulsatile arteries, confirming the measured impedance signal at the wrist contains the pulsatile information from both arteries. This work is the first simulation and phantom investigation into two synchronously pulsatile arteries under BIA in the distal forearm, providing a better insight and understanding in the morphology of measured impedance signals. Future research can accordingly select either a small spacing 4-spot electrode configuration for a single artery sensing or a band electrode configuration for overall pulsatile arteries sensing. A more accurate estimation of blood volume change and pulse wave analysis (PWA) could help to develop cuffless blood pressure measurement (BPM).

Uncertainty quantification of microcirculatory characteristic parameters for recognition of cardiovascular diseases

BackgroundCardiovascular disease is one of the leading causes of death worldwide. However, according to studies, 90% of cardiovascular diseases can be prevented. Cardiovascular function parameters are an important basis for the diagnosis of cardiovascular diseases. The pulse wave also contains a wealth of physiological and pathological information, which can reflect the trend of cardiac function parameters at an early stage, so the measurement and analysis of the pulse wave signal becomes more and more important. The wearable pulse signal acquisition device has gradually become a new trend. In the mobile health scenario, convenient use is the prerequisite for long-term and rapid health monitoring. The data containing diverse pulse wave signals is the basis for obtaining more comprehensive and accurate human physiopathological information. Accurate data analysis and processing is the key to realizing the important goal of cardiovascular health monitoring. ObjectiveBased on the concept of mobile health care, wearable devices are developed to obtain physiological signals. The zero-dimensional model and the optimization algorithm are combined to complete the uncertainty quantification of the microcirculation parameters. Then, a feature set containing the cardiovasvular parameters can be constructed. The machine learning algorithm can be used to build a model that can accurately realize cardiovascular disease identification. MethodsThis paper adopts laboratory-developed equipment to acquire the wrist pulse wave and fingertip volume pulse wave. A total of 323 samples were collected from healthy populations, hypertensive patients and patients with coronary heart disease (CHD). The pulse blood flow model in fingertip microcirculation is established, and the uncertainty quantification of model parameters is completed based on slime mold algorithm (SMA). After comparing and analyzing the performance of four algorithms on pulse wave classification, the identification model of cardiovascular diseases is established based on the microcirculatory characteristic parameter set and random forest algorithm (RF). ResultsRF showed good classification performance among the four classification algorithms. The identification accuracy of the model built on the microcirculatory characteristic parameter set and RF algorithm all reached more than 88%. The highest recognition accuracy was 95.51% for coronary heart disease samples, 92.11% for healthy samples, and 88.55% for hypertensive samples. It can be seen that the model based on RF algorithm has a good ability to distinguish the characteristic parameters in different cardiovascular health states. ConclusionsThe wearable device designed in this paper can facilitate the daily health monitoring of cardiovascular disease. By using the combination of the physical model and machine learning model, the uncertainty quantification of microcirculation parameters and the identification of cardiovascular disease was finally completed. The recognition model based on machine learning provides a new idea and method for the research of cardiovascular health monitoring through pulse waves.

The Capacitive Sensing of the Pulsatile Liquid Flow—Investigation on a Physical Vascular Model

This article investigates a prospective capacitive sensing method for the measurement of physical characteristics of a pulsatile liquid flow. It was tested on a physical vascular model. The volume pulse wave sensor holds a high sensitivity and thus great potential in the field of industrial applications and also in biomedical applications where we also encounter a pulsating flow of blood. Two types of capacity sensors were developed and tested on our blood vessel model, currently used for the simulation of pulse wave propagation with the possibility of changes in vessel properties and many setups are reached for testing different pulse wave propagations. The newly developed capacitive sensor detects the capacity change of pulsating liquid flow in the vascular model. Data from the capacitive sensor are compared with two reference sensors, one for direct pressure sensing and the second for noncontact optical sensing of changes in diameter. The signal processing is used for all three types of sensors and analysis in the time and frequency domain to determine the accuracy. The use of capacitive sensors is promising since it can measure a negligible change in the diameter of the vessel in the range of tens of femtofarads (fF). We can confirm that the high precision measurement is dependent on the environment, which can cause the capacity change, but with proper shielding it can be eliminated.

A preliminary study on the effect of breathing on heart rate and blood pressure variability in patients with chronic diseases with abnormal sleep breathing

ObjectiveTo analyze the relationship between heart rate and blood pressure variability and respiration in patients with chronic respiratory disorders during night sleep.Methods16 patients with chronic diseases with abnormal sleep and respiration were included. Polysomnography was used to analyze the R‐R interval of nasal airflow electrocardiogram in normal stable breathing period and wave breathing period (OB) during nighttime sleep, and the variation of blood pressure based on finger‐tip photoelectric volume pulse wave (PPG) and pulse wave conduction time (PTT).The ResultsThe ratio of the number of respiratory cycles to the number of heart rate variability cycles (B‐n / HRV‐n) was (1.00 ± 0.04), to the number of systolic blood pressure (SBP) variability cycles (B‐n / SBPV‐n) was (1.02 ± 0.10), and diastolic blood pressure (DBP) variability cycles (B‐n / DBPV‐B‐n) was (1.00 ± 0.11), The ratio of respiratory cycle number to heart rate variability cycle number (OB‐n / OB‐HRV‐n) during OB was (1.22 ± 0.18). The ratio of respiratory cycle number to systolic blood pressure variation cycle number (OB‐n / OB‐SBPV‐n) was (1.19 ± 0.22), and DBP(OB‐n / OB‐DBPV‐n) was (1.15 ± 0.15), both of which were higher than those in normal stable breathing period (P &lt; 0.01). During the normal and stable breathing period, the average amplitude of heart rate variability (HRV‐B‐M) of each respiratory cycle rhythm was (2.64 ± 1.59) bpm, the average amplitude of systolic blood pressure variability (SBPV‐B‐M) of each respiratory cycle rhythm was (2.83 ± 1.22) mmhg, and diastolic blood pressure variability (DBPV‐B‐M) was (2.40 ± 0.86) mmhg, which were slightly higher than those of the normal people, but there was no significant difference compared with the normal people and hypertensive patients without sleep apnea. The mean amplitude of heart rate variability (OB‐HRV‐B‐M) at each respiratory cycle rhythm in OB period was (3.56 ± 1.57) bpm, the mean amplitude of heart rate variability (OB‐HRV‐OB‐M) at each OB period was (13.75 ± 4.25) bpm, The average amplitude of diastolic blood pressure variability (OB‐DBPV‐B‐M) was (2.82 ± 1.95) mmhg, which was higher than that in normal stable respiratory period. The difference between OB‐SBPV‐B‐M and normal stable respiratory systolic blood pressure variability (SBPV‐B‐M) was significant. The variation range of systolic blood pressure (OB‐SBPV‐OB‐M) in each OB cycle was (16.83 ± 9.29) mmhg, which was much larger than that of OB‐SBPV‐B‐M and SBPV‐B‐M (P &lt; 0.01).ConclusionThe variations of blood pressure and heart rate in patients with chronic respiratory disorders during normal and stable breathing at night are similar to those in normal people and hypertensive patients without sleep respiratory disorders in the same period in our laboratory, The variation amplitude of heart rate and blood pressure in wavy breathing period was greater than that in normal and stable breathing period .confirming that the variation of heart rate and blood pressure was respiratory origin.

Evaluation of autonomic nervous system responses during isometric handgrip exercise using nonlinear analysis of heart rate variability.

[Purpose] The purpose of this study was to examine, using a plethysmogram of the fingertips, autonomic responses at motor intensities of 30% or 50% of maximum voluntary contraction (MVC) during isometric handgrip exercise (IHG). [Participants and Methods] The participants of this study were 15 healthy persons. The finger volume pulse wave of each participant was measured continuously, using a BACS Advance equipment (TAOS Co.), for a total of 17 minutes: 5 minutes before IHG (Pre), 2 minutes during IHG (IHG), the first 5 minutes after IHG (Post 5), and then the second 5 minutes after IHG (Post 10). To evaluate autonomic nervous system activity, we used the Detrended fluctuation analysis (DFA) and Approximate Entropy (ApEn). [Results] During IHG, the pulse rate was significantly higher and the ApEn value was significantly lower than during the other periods of measurement. Compared to other analyzed parameters, ApEn decreased during IHG, but returned to its initial Pre period level during the Post 5 period. The α1 value derived from the DFA analysis remained at a value of 1 during each measurement time point, indicating the absence of malfunctions in autonomic response. [Conclusion] Isometric handgrip exercise with 30% MVC seemed to be useful for the assessment of autonomic nervous system response.

Low-Frequency Vibration Facilitates Post-Exercise Cardiovascular Autonomic Recovery

It is important to use short breaks to accelerate post-exercise recovery in sports. Previous studies have revealed that vibration can reduce post-exercise muscle soreness. However, there is still high heterogeneity in the effects of vibration on cardiovascular autonomic activities, and most studies to date have focused on high-frequency vibration. This study aimed to investigate the effect of low-frequency lower-body vibration (LBV) on post-exercise changes in heart rate variability and peripheral arterial tone. Ten men and 9 women aged 20 to 25 were recruited for this study. Each subject visited the testing room three times with at least 2 days in between. Each time, the subject received one of the three different vibration frequencies (0, 5, and 15 Hz) in a random order in the sitting position for 10 minutes. LBV was performed immediately after a static standing (control) test and 3-min-step test. Heart rate variability and digital volume pulse wave were recorded during the vibration phase (V1: vibration 0-5 minutes; V2: 6-10 minutes) and the recovery phase (Rc1: recovery phase 11-15 minutes; Rc2: 16-20 minutes). The result of digital pulse wave analysis showed that the reflection index (RI) under 15 Hz decreased during V1. Heart rate of the 15-Hz group also decreased during Rc1 and Rc2. According to the analysis of heart rate variability, low-frequency power/high-frequency power (LF/HF) decreased and normalized high-frequency power (nHF) increased during V2, Rc1 and Rc2 under 15 Hz and, during Rc2 under 5 Hz vibration. This study confirmed that the application of low-frequency LBV after exercise can reduce peripheral vascular tone, accelerate heart rate recovery, decrease cardiac sympathetic nerve activity, and promote parasympathetic nerve activity. The effect was more pronounced at 15 Hz than at 5 Hz. The findings provide a method to accelerate cardiovascular autonomic recovery after exercise.

A Light Adaptive Heart Rate Detection Method Based on Webcam

In order to extract the pulse wave signal of blood volume effectively in the case of uneven light, a light-adaptive heart rate detection method based on webcam was proposed. In this method, adaptive gamma transform is applied to face image sequence to eliminate the influence of illumination. The pulse wave source signal was extracted from the forehead area and the blood volume pulse wave was obtained by wavelet filtering. The heart rate is estimated by Fourier transform analysis. The Bland-Altman analysis indicates that the method used in this paper is in good agreement with the measurement results of the electronic sphygmomanometer, and the adaptive gamma transformation used in this paper eliminates the influence of light interference, and the measurement error of heart rate is significantly reduced, which is completely able to meet the requirements of daily heart rate monitoring.

Central serous chorioretinopathy and heart rate variability analysis with a smartphone application

The purpose of this study was to quantitatively analyze heart rate variability (HRV) in patients with central serous chorioretinopathy (CSC) by using a smartphone-based application (ANBAI: DUMSCO Inc.) for measurement, and to clarify its relationships with CSC. The subjects were 64 CSC patients (mean age 48.7 ± 7.6 years, 57 males and 7 females). After providing consent, the patients downloaded ANBAI apps to their smartphones. HRV was measured by photoelectric volume pulse wave measurement with a smartphone camera each morning for a minimum of 1 week. The primary outcome was to analyze HRV by calculating log LF/HF (Low Frequency/High Frequency components), an index of autonomic tone, which was then compared with a control group of 35,226 individuals from the application. Secondary outcome measures included disease duration, body mass index, exercise habits, smoking history, steroid use, occupation, lifestyle regularity, psychological fatigue, physical fatigue, and average sleep time. The log LF/HF was significantly higher in the patient group than in the control group (P < 0.001). Log LF/HF was significantly lower in patients with exercise habits as a factor contributing to log LF/HF in the patient group (P = 0.019). Analysis of HRV in CSC patients showed an impairment of the autonomic nervous system. Exercise habits may also be associated with CSC.

A wearable blood oxygen saturation monitoring system based on bluetooth low energy technology

Dynamic monitoring of blood oxygen saturation value is an important method for the prevention and treatment of chronic cardiovascular disease. In order to meet the design requirements of wearable mobile medical, this paper uses the main controller to read, filter, and calculate pulse rate and blood oxygen value, and saturate the pulse signal and blood oxygen through the Bluetooth low-power module. The degree value and pulse rate value are transmitted to the Android smartphone, and the APP on the Android phone side manages the user’s physiological parameters and establishes a personal health file. Monitoring of blood oxygen saturation in a dynamic environment can be affected by severe motion disturbances. Aiming at this problem, this paper proposes a new adaptive cancellation algorithm based on adaptive filtering. Based on the interference analysis of the photoelectric volume pulse wave signal in a dynamic environment, this paper uses the envelope information of the PPG (Photoplethysmography) signal to extract the AC component of the photoelectric volume pulse wave signal, and construct interference-related signals as reference signals and perform adaptive filtering to suppress motion interference. The adaptive cancellation algorithm proposed in this paper performs digital signal processing on the collected original information and analyzes the calculation results. Comparing the calculated results with those of the DST (Discrete Saturation Transform) signal extraction technology, the effectiveness of the algorithm in eliminating motion interference is verified, and the anti-interference ability and time complexity of the algorithm under severe motion are verified.

Pharmacodynamic Analysis of the Influence of Propofol on Left Ventricular Long-Axis Systolic Performance in Cardiac Surgical Patients.

BackgroundPropofol induced a decline in the left ventricular (LV) systolic performance in non-cardiac surgery. We tested the hypothesis that propofol decreased the LV contractile function by dose dependent manner in cardiac surgery patients.MethodsAnesthesia was maintained with target-controlled infusions of propofol and remifentanil in cardiac surgery patients. With a fixed effect-site concentration (Ce) of remifentanil (20 ng/mL) after sternotomy, the Ce of propofol was adjusted to maintain a Bispectral index of 40–60 (Ce1). Mitral annular Doppler tissue image tracings and other echocardiographic variables, including end-diastolic and end-systolic volumes, stroke volume, and mitral inflow pulse wave Doppler profile at Ce1, were recorded using transesophageal echocardiography. Echocardiographic recordings were repeated after the Ce-values of propofol were doubled and tripled at 10-minute intervals (defined as Ce2 and Ce3, respectively). Serial changes in echocardiographic variables for each Ce of propofol were assessed using generalized linear mixed effect modeling. The pharmacodynamic relationship between the Ce of propofol and peak systolic mitral annular velocity (Sm) was analyzed by logistic regression using non-linear mixed effect modeling (NONMEM).ResultsMeans of Ce1, Ce2, and Ce3 were 0.8, 1.6, and 2.4 μg/mL, respectively, and their means of Sm (95% confidence interval) were 9.7 (9.3–10.2), 8.7 (8.2–9.1), and 7.5 cm/sec (7.0–8.0), respectively (P < 0.01). Ce values of propofol and Sm showed a significant inter-correlation and predictability (intercept, 10.8; slope–1.0 in generalized mixed linear modeling; P < 0.01). Ce values producing 10% and 20% decline of Sm with 50%-probability were 1.4 and 2.1 μg/mL, respectively.ConclusionPropofol reduces LV systolic long-axis performance in a dose-dependent manner.Trial RegistrationClinicalTrials.gov Identifier: NCT01826149

Parameters Extracted From Arterial Pulse Waves as Markers of Atherosclerotic Changes: Performance and Repeatability.

Arterial diseases are significant and increasing cause of mortality and morbidity. In this study, we analyze and compare the discrimination capability of different arterial pulse wave (PW) based indices, both earlier proposed and novel ones, for describing the vascular health. The repeatability of the indices is also evaluated. Both volume PWs and dynamic pressure PWs are recorded by using photoplethysmographic and electromechanical film (EMFi) sensors connected to a wireless body sensor network. The study population consists of 82 subjects, 30 atherosclerotic patients, and 52 control subjects. In addition, day-to-day variability of the derived indices is studied with ten test subjects examined on three different days. The results are evaluated in terms of statistical tests and receiver operating characteristic (ROC) curves as well as coefficient of variation (CV) and intraclass correlation coefficient (ICC). Altogether 24 out of the evaluated 40 PW parameters showed statistical differences ( or less) between controls and atherosclerotic patients. Maximum area under curve was 0.88. Most of the indices had ICCs higher than 0.8 and average CVs less than 0.1. The study shows that the amplitude ratios and time intervals between different PW peaks could be a useful additional tool for the detection of atherosclerosis. The results encourage us for further studies in this field. Up to our knowledge, the performance and the repeatability of different PW derived indices have previously not been studied and compared with each other this extensively. Our findings also provide evidence for the utility of PW measurements for the detection of atherosclerotic changes.

Research of Multifunctional Fitness Equipment Monitor Based on Photoelectric Sensor

Health is the eternal topic that human concern, especially in modern times, and equipment fitness is an important part of people's fitness. People's demand for fitness equipment is becoming more and more rational. With the rapid development of information technology and electronic technology, using photoelectric methods to detect physiology index of human body has become an unescapable trend. Therefore, bringing in some advanced technology in other fields to design a portable, noninvasive, low-cost multifunctional human physiological health index monitor has a great significance. This thesis firstly introduces the situation of fitness equipment, then studies people's demand for intelligent fitness equipment, and specifically proposes the measurement scheme of human physical health index based on the photoelectric sensor. By studying the production principle of photoelectric volume pulse wave , this thesis sets up the experimental platform to prove the effectiveness of the proposed method. Finally, this topic research has shown that this kind of intelligent fitness equipment like multifunctional fitness monitor based on the photoelectric sensor can effectively improve people's exercise styles, and has a large market application prospect.

Blood Pressure Estimation Accoording to Photoplethysmographic Signal Steepness

Abstract. The purpose of this paper is to prove the assumption that there is a correlation between the systolic blood pressure and the photoplethysmographic signal steepness. A method for indirect systolic blood pressure estimation based on photoplethysmographic signal steepness is proposed in this paper. Method: It is proved that based on Hooke’s law, the steepness of pressure and volume (diameter) of pulse waves differ by a constant. The coefficient for calculating arterial blood pressure when volume pulse wave steepness is known is presented in this paper. The Windkessel model is selected for the modeling. Experimental evaluation is based on veloergometrical trials. Volume pulse wave was obtained using a photoplethysmography device that is put on a finger. Blood pressure was measured using a semi-automatic OMRON blood pressure monitor. Results: The simulation of an arterial system using the Windkessel model shows that the steepness of pressure and volume pulse waves correlate. Ten veloergometrical trials were performed during the experimental evaluation. A significant 0.855±0.025 (p &lt; 0.001) correlation between the photoplethysmographic signal steepness and the systolic blood pressure was obtained. The calculated and measured blood pressure values vary no more than ±5mmHg. Conclusions: The results demonstrate that the photoplethysmographic signal wavefront can be successfully applied in wearable devices that can be used for constant 24 hour registration of blood pressure for both home use and clinical practice.DOI: http://dx.doi.org/10.5755/j01.itc.44.4.12562

Age Dependence of Arterial Pulse Wave Parameters Extracted From Dynamic Blood Pressure and Blood Volume Pulse Waves.

Atherosclerosis is a significant cause of mortality in the aged population, and it affects arterial wall properties causing differences in measured arterial pulse wave (PW). In this study, both dynamic arterial blood pressure PWs and blood volume PWs are analyzed. The PWs are recorded noninvasively from multiple measurement points from the upper and lower limbs from 52 healthy (22-90-year-old) volunteers without known cardiovascular diseases. For each signal, various parameters earlier proposed in the literature are computed, and 25 different novel parameters are formed by combining these parameters. The results are evaluated in terms of age and heart rate (HR) dependence of the parameters. In general, the results show that 14 out of 25 tested combined parameters have stronger age dependence than any of the individual parameters. The highest obtained linear correlation coefficients between the age and combined parameter and individual parameter equal to 0.85 ( ) and 0.79 ( ), respectively. Most of the combined parameters have also improved discrimination capability when classifying the test subjects into different age groups. This is a promising result for further studies, but indicate that the age dependence of the parameters must be taken into account in further studies with atherosclerotic patients.

Digital Photoplethysmography for Assessment of Arterial Stiffness: Repeatability and Comparison with Applanation Tonometry.

IntroductionArterial stiffness is an independent risk factor for cardiovascular morbidity and can be assessed by applanation tonometry by measuring pulse wave velocity (PWV) and augmentation index (AIX) by pressure pulse wave analysis (PWA). As an inexpensive and operator independent alternative, photoelectric plethysmography (PPG) has been introduced with analysis of the digital volume pulse wave (DPA) and its second derivatives of wave reflections.ObjectiveThe objective was to investigate the repeatability of arterial stiffness parameters measured by digital pulse wave analysis (DPA) and the associations to applanation tonometry parameters.Methods and Results112 pregnant and non-pregnant individuals of different ages and genders were examined with SphygmoCor arterial wall tonometry and Meridian DPA finger photoplethysmography. Coefficients of repeatability, Bland-Altman plots, intraclass correlation coefficients and correlations to heart rate (HR) and body height were calculated for DPA variables, and the DPA variables were compared to tonometry variables left ventricular ejection time (LVET), PWV and AIX. No DPA variable showed any systematic measurement error or excellent repeatability, but dicrotic index (DI), dicrotic dilatation index (DDI), cardiac ejection elasticity index (EEI), aging index (AI) and second derivatives of the crude pulse wave curve, b/a and e/a, showed good repeatability. Overall, the correlations to AIX were better than to PWV, with correlations coefficients >0.70 for EEI, AI and b/a. Considering the level of repeatability and the correlations to tonometry, the overall best DPA parameters were EEI, AI and b/a. The two pansystolic time parameters, ejection time compensated (ETc) by DPA and LVET by tonometry, showed a significant but weak correlation.ConclusionFor estimation of the LV function, ETc, EEI and b/a are suitable, for large artery stiffness EEI, and for small arteries DI and DDI. The only global parameter, AI, showed a high repeatability and the overall best correlations with AIX and PWV.

Detecting differences in volume pulse wave parameters among fingers and toes in four different postures.

The measurement of volume pulse waves may be easily affected based on the measured position (different fingers or toes), body posture, as well as other factors. Therefore, interferences during measurement need to be removed. For this study, relevant parameters of volume pulse wave were obtained by changing the affecting factors. The data were analyzed in order to indicate the differences in volume pulse wave parameters among different fingers and toes in four postures. Results showed that when subjects were lying, inclined or in a sitting posture, volume pulse wave parameters of the index finger, middle finger and ring finger on both hands displayed no apparent differences. When subjects were in a sitting posture, volume pulse wave parameters of the big, second and third toes on both feet showed no significant differences.

Remote measurements of heart and respiration rates for telemedicine.

Non-contact and low-cost measurements of heart and respiration rates are highly desirable for telemedicine. Here, we describe a novel technique to extract blood volume pulse and respiratory wave from a single channel images captured by a video camera for both day and night conditions. The principle of our technique is to uncover the temporal dynamics of heart beat and breathing rate through delay-coordinate transformation and independent component analysis-based deconstruction of the single channel images. Our method further achieves robust elimination of false positives via applying ratio-variation probability distributions filtering approaches. Moreover, it enables a much needed low-cost means for preventing sudden infant death syndrome in new born infants and detecting stroke and heart attack in elderly population in home environments. This noncontact-based method can also be applied to a variety of animal model organisms for biomedical research.

Epicardial Fat Thickness Correlates With Carotid Intima-Media Thickness, Arterial Stiffness, and Cardiac Geometry in Children and Adolescents

To determine the association between epicardial fat thickness and carotid arterial stiffness, carotid intima-media thickness (CMIT), left atrial (LA) volume, and left-ventricular (LV) geometry parameters in obese children and adolescents compared with controls. A case-control study was performed in 96 children and adolescents (obese n = 66, controls n = 30) age 9-16 years old (38 female and 58 male, mean age 11.7 ± 2.8 years) undergoing transthoracic echocardiography and carotid artery ultrasound. Clinical, anthropometric, and biochemical determinations were also recorded. Epicardial fat thickness (2.76 ± 1.2 vs. 1.36 ± 0.7 mm, p < 0.001), LA volume (35.7 ± 13.2 vs. 28.9 ± 9.8 mL, p = 0.008), LV mass (118.3 ± 38.6 vs. 96.4 ± 35.4 mL, p = 0.008), CIMT (0.48 ± 0.07 vs. 0.44 ± 0.05 mm, p = 0.019), and local pulse wave velocity (LPWV; 3.7 ± 0.5 vs. 3.2 ± 0.4 m/seg, p = 0.007) were significantly increased in obese children and adolescents compared with controls. Epicardial fat showed a significant and positive correlation with LA volume, LV mass, and LPWV as well as a significant and independent association with increased CIMT (odds ratio (OR) = 3.19 [1.88-7.99], p = 0.005) in the study population. Epicardial fat thickness is linked to obesity, carotid subclinical atherosclerosis, and cardiac geometry parameters and might be a useful tool for the cardiovascular risk stratification in children and adolescents.

Abdominal visceral and subcutaneous fat increase, insulin resistance and hyperlipidemia in testicular cancer patients treated with cisplatin-based chemotherapy

Background. Testicular cancer survivors treated with chemotherapy are at increased risk for metabolic syndrome (MetS) and cardiovascular disease (CVD). We explored acute effects of chemotherapy by assessing metabolic factors, abdominal fat volume, hepatic triglyceride content (HTC) and aortic wall stiffness. Material and methods. We studied 19 testicular cancer patients (age 20–54 years) before, at three and nine months after the start of chemotherapy. Blood serum was analyzed for lipids, glucose and insulin. Abdominal visceral and subcutaneous fat volume and aortic pulse wave velocity were assessed by magnetic resonance imaging (MRI) techniques; HTC was measured by proton MR spectroscopy. Results. Three months after start of chemotherapy visceral abdominal fat volume had significantly increased from 202 ± 141 to 237 ± 153 ml (p = 0.009) whereas body mass index and subcutaneous fat volume significantly increased nine months after treatment from 24.4 ± 4.0 to 26.4 ± 4.1 kg/m2 (p = 0.01) and from 556 ± 394 to 668 ± 460 ml (p = 0.002) respectively. Serum total cholesterol, low-density lipoprotein cholesterol and insulin also significantly increased three months after start of treatment from 4.88 ± 1.1 to 5.61 ± 1.50 mmol/l (p = 0.002), 3.31 ± 1.16 to 3.73 ± 1.41 mmol/l (p = 0.02) and 5.7 ± 4.4 to 9.6 ± 6.3 mU/ml (p = 0.03), respectively. Nine months after start of chemotherapy serum lipid and insulin concentrations had returned to baseline. HTC increased in seven of the 19 patients (36.8%) during follow-up. Aortic pulse wave velocity remained unchanged at the three time points measured. Conclusion. Cisplatin-based chemotherapy was associated with acute insulin resistance, dyslipidemia and an immediate increase in abdominal visceral adipose tissue and abdominal subcutaneous adipose tissue in testicular cancer patients. A large prospective cohort study with long follow-up is warranted to characterize the time course and relationship between acutely induced obesity and hypercholesterolemia and the development of metabolic syndrome and CVD years later in individual testicular cancer survivors.