Preclinical Assessment of a Novel Cardiovascular Telemedicine System

2020 ◽  
Author(s):  
Dániel Kulin ◽  
Flóra Antali ◽  
Sándor Kulin ◽  
Dina Wafa ◽  
Konrád István Lucz ◽  
...  
Keyword(s):  
Pulse Wave ◽  
Pulse Contour ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Second Derivative ◽  
Healthy Individuals ◽  
Telemedicine System ◽  
Cardiovascular Morbidity And Mortality ◽  
Digital Pulse ◽  
Ventricular Ejection Time

Abstract Background Introduction of telemonitoring systems to patient care which provide extensive information about the cardiovascular status of the patient is a promising direction to reduce cardiovascular morbidity and mortality. Our team has developed a telemedical system which is based on the photoplethysmographic detection of the digital arterial pulse wave. The system incorporates a cloud-based automated algorithm which analyses the pulse contour to provide 15 scientifically established parameters for versatile characterization of cardiovascular function. The aim of the current study was to assess the variability of the measurements to test the applicability of the tool before clinical use. We assessed the repeatability of the measurements by detecting stable artificial signals, and also test-retest variability by repeatedly examining the pulse contours of healthy individuals under standardized conditions. Results Most contour parameters (stiffness index, reflection index, left ventricular ejection time index and mean interbeat intervals) are measured with high repeatability (coefficients of variation (CV) < 1% for each parameter), and exhibit acceptable intrapersonal fluctuations (CVs < 10%). However, some parameters derived from the second derivative of the pulse wave seem to be more variable (aging index, d/a ratio). This is explained by the typical alterations of the pulse wave under specific circumstances, which cause the flattening or complete disappearance of c and d inflections on the second derivative. Conclusion Our measurements proved that our telemonitoring system detects and analyses digital pulse contours with high accuracy and highlighted that second derivative parameters should be interpreted cautiously. We recommend the evaluation of these parameters only in those measurements where c and d points are detected reliably. Pulse contour parameters are stable in healthy individuals under standardized conditions, which allows detection of subtle abnormal alterations by the remote surveillance system.

scholarly journals Preclinical, Multi-Aspect Assessment of the Reliability of a Photoplethysmography-Based Telemonitoring System to Track Cardiovascular Status

2020 ◽  
Vol 10 (22) ◽  
pp. 7977
Author(s):  
Dániel Kulin ◽  
Flóra Antali ◽  
Sándor Kulin ◽  
Dina Wafa ◽  
Konrád István Lucz ◽  
...  
Keyword(s):  
Reliable Method ◽  
High Accuracy ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Healthy Individuals ◽  
Contour Analysis ◽  
Telemedicine System ◽  
Retest Reliability ◽  
Ventricular Ejection Time ◽  
Test Retest Reliability

Telemonitoring systems equipped with photoplethysmography-based contour analysis of the digital arterial volume pulse (DVP) can be optimal tools for remote monitoring of cardiovascular patients; however, the method is known to be sensitive to errors. We aimed to show that DVP analysis is a reliable method to track cardiovascular status. We used our proprietary SCN4ALL telemedicine system and analyzed nine parameters derived from the DVP and its second derivative (SDDVP). First, we assessed the repeatability of system measurements by detecting artificial signals. Then test–retest reliability of human measurements was evaluated in healthy individuals under standardized conditions. The SCN4ALL system analyzed each parameter with high accuracy (coefficients of variation (CVs) < 1%). Test–retest reliability of most parameters (stiffness index, reflection index, left ventricular ejection time index, b/a, heart rate) was satisfactory (CVs < 10%) in healthy individuals. However, aging index and d/a ratio derived from the SDDVP were more variable. Photoplethysmography-based pulse contour analysis is a reliable method to monitor cardiovascular status if measurements are performed with a system of high accuracy. Our results highlighted that SDDVP parameters can be interpreted with limitations due to (patho)physiological variations of the DVP. We recommend the evaluation of these parameters only in measurements where all inflections of SDDVP are detected reliably.

scholarly journals Sauna exposure leads to improved arterial compliance: Findings from a non-randomised experimental study

2017 ◽  
Vol 25 (2) ◽  
pp. 130-138 ◽  
Author(s):  
Earric Lee ◽  
Tanjaniina Laukkanen ◽  
Setor K Kunutsor ◽  
Hassan Khan ◽  
Peter Willeit ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Mean Arterial Pressure ◽  
Pulse Wave ◽  
Left Ventricular ◽  
Ventricular Ejection ◽  
Left Ventricular Ejection ◽  
Ejection Time ◽  
Left Ventricular Ejection Time ◽  
Sauna Bathing ◽  
Ventricular Ejection Time

Background Heat therapy has been suggested to improve cardiovascular function. However, the effects of hot sauna exposure on arterial compliance and the dynamics of blood flow and pressure have not been well documented. Thus, we investigated the short-term effects of sauna bathing on arterial stiffness and haemodynamics. Design The design was an experimental non-randomised study. Methods There were 102 asymptomatic participants (mean age, 51.9 years) who had at least one cardiovascular risk factor. Participants were exposed to a single sauna session (duration: 30 min; temperature: 73℃; humidity: 10–20%). Pulse wave velocity, augmentation index, heart rate, blood pressure, mean arterial pressure, pulse pressure, augmented pressure and left ventricular ejection time were assessed before, immediately after, and 30 min after a single sauna session. Results Sauna bathing led to reductions in pulse wave velocity, blood pressure, mean arterial pressure and left ventricular ejection time. Mean pulse wave velocity value before sauna was 9.8 m/s and decreased to 8.6 m/s immediately after sauna bathing ( p < 0.001 for difference), and was 9.0 m/s after the 30-minute recovery period ( p < 0.001 for analysis of variance). Systolic blood pressure was 137 mm Hg before sauna bathing, decreasing to 130 mm Hg after sauna ( p < 0.001), which remained sustained during the 30-minute recovery phase ( p < 0.001 for analysis of variance). After a single sauna session, diastolic blood pressure decreased from 82 to 75 mm Hg, mean arterial pressure from 99.4 to 93.6 mm Hg and left ventricular ejection time from 307 to 278 m/s ( p < 0.001 for all differences). Pulse pressure was 42.7 mm Hg before the sauna, 44.9 mm Hg immediately after the sauna, and reduced to 39.3 mm Hg after 30-minutes recovery ( p < 0.001 for analysis of variance). Heart rate increased from 65 to 81 beats/min post-sauna ( p < 0.001); there were no significant changes for augmented pressure and pulse pressure amplification. Conclusion This study shows that pulse wave velocity, systolic blood pressure, diastolic blood pressure, mean arterial pressure, left ventricular ejection time and diastolic time decreased immediately after a 30-minute sauna session. Decreases in systolic blood pressure and left ventricular ejection time were sustained during the 30-minute recovery phase.

Left ventricular ejection time, not heart rate, is an independent correlate of aortic pulse wave velocity

2013 ◽  
Vol 115 (11) ◽  
pp. 1610-1617 ◽  
Author(s):  
Paolo Salvi ◽  
Carlo Palombo ◽  
Giovanni Matteo Salvi ◽  
Carlos Labat ◽  
Gianfranco Parati ◽  
...  
Keyword(s):  
Pulse Wave Velocity ◽  
Wave Velocity ◽  
Pulse Wave ◽  
Left Ventricular ◽  
Ventricular Ejection ◽  
Left Ventricular Ejection ◽  
Heart Period ◽  
Ejection Time ◽  
Left Ventricular Ejection Time ◽  
Ventricular Ejection Time

Several studies showed a positive association between heart rate and pulse wave velocity, a sensitive marker of arterial stiffness. However, no study involving a large population has specifically addressed the dependence of pulse wave velocity on different components of the cardiac cycle. The aim of this study was to explore in subjects of different age the link between pulse wave velocity with heart period (the reciprocal of heart rate) and the temporal components of the cardiac cycle such as left ventricular ejection time and diastolic time. Carotid-femoral pulse wave velocity was assessed in 3,020 untreated subjects (1,107 men). Heart period, left ventricular ejection time, diastolic time, and early-systolic dP/dt were determined by carotid pulse wave analysis with high-fidelity applanation tonometry. An inverse association was found between pulse wave velocity and left ventricular ejection time at all ages (<25 years, r2 = 0.043; 25–44 years, r2 = 0.103; 45–64 years, r2 = 0.079; 65–84 years, r2 = 0.044; ≥85 years, r2 = 0.022; P < 0.0001 for all). A significant ( P < 0.0001) negative but always weaker correlation between pulse wave velocity and heart period was also found, with the exception of the youngest subjects ( P = 0.20). A significant positive correlation was also found between pulse wave velocity and dP/dt ( P < 0.0001). With multiple stepwise regression analysis, left ventricular ejection time and dP/dt remained the only determinant of pulse wave velocity at all ages, whereas the contribution of heart period no longer became significant. Our data demonstrate that pulse wave velocity is more closely related to left ventricular systolic function than to heart period. This may have methodological and pathophysiological implications.

Abstract P294: Greater Peripheral Vasoconstriction During Mental Stress Predicts Adverse Cardiovascular Outcomes

Circulation ◽  
2018 ◽  
Vol 137 (suppl_1) ◽  
Author(s):  
Jeong Hwan Kim ◽  
Muhammad Hammadah ◽  
Ibhar Al Mheid ◽  
Kobina Wilmot ◽  
Ronnie Ramadan ◽  
...  
Keyword(s):  
Mental Stress ◽  
Wave Amplitude ◽  
Pulse Wave ◽  
Smoking Status ◽  
Left Ventricular ◽  
Cardiovascular Outcomes ◽  
Peripheral Vasoconstriction ◽  
Pulse Wave Amplitude ◽  
Digital Pulse ◽  
Peripheral Arterial

Introduction: Peripheral arterial vasoconstriction during mental stress (MS) has been associated with mental stress-induced myocardial ischemia, which in turn has been linked with worse cardiovascular outcomes. It is unknown whether the magnitude of peripheral vasoconstriction with MS is predictive of long term outcomes. Hypothesis: We hypothesized that greater peripheral arterial vasoconstriction during MS would be associated with adverse events among patients with coronary artery disease (CAD). Methods: Four hundred sixty-three patients with stable CAD and normal left ventricular function, (age 63±9, 75% male, 27% Black, EF 60±8 %) underwent MS testing with a standardized public speaking stressor. Digital pulse wave amplitude was continuously measured at baseline and during MS using peripheral arterial tonometry (PAT), and the PAT ratio of pulse wave amplitude (during mental stress/ baseline) was calculated. Cox proportional hazard models were calculated to examine the association between the PAT ratio and outcomes. Results: Median PAT ratio during MS was 0.68, indicating 32% average constriction with MS compared to rest. Subjects with greater peripheral constriction [low (<median) PAT ratio] were more likely to be male (80% vs. 70%, P=0.008) compared to those with PAT ratio ≥median, but their risk factor profiles were similar. During 2.8±0.5 year follow-up, 64 patients had adverse cardiac events including 7 cardiovascular deaths, 19 MI, and 54 revascularization events. After adjusting for age, sex, race, hypertension, diabetes, current smoking status, and prior MI, those with low PAT ratio had a greater risk of CV death/MI (HR[hazard ratio] 2.49, 95% CI [1.04-5.99]) and CV death/MI/revascularization (HR 1.77, 95% CI [1.03-3.04]) compared to those with high PAT ratio. Conclusion: Greater peripheral arterial vasoconstriction with MS is associated with a higher risk of adverse cardiovascular outcomes in patients with CAD.

Abstract P161: Effect of Yoga Program on Cardiovascular Function in Elderly with Stage-I Hypertension

Circulation ◽  
2016 ◽  
Vol 133 (suppl_1) ◽  
Author(s):  
Satish G Patil
Keyword(s):  
Cardiovascular Function ◽  
Left Ventricular ◽  
Stage I ◽  
Left Ventricular Ejection ◽  
Control Group ◽  
Yoga Practice ◽  
Yoga Group ◽  
The Mean ◽  
Group Change ◽  
Ventricular Ejection Time

Introduction: Hypertension is a major cause of cardiovascular (CV) morbidity and mortality in elderly population. Hypertension along with aging leads to left ventricular hypertrophy, systolic and diastolic dysfunction and congestive heart failure. We aimed to determine the effect of yoga program on cardiovascular indices in elderly with stage-I hypertension. Hypothesis: We hypothesize that yoga lifestyle modality may induce significant beneficial changes in cardiovascular function in elderly individuals with hypertension. Yoga program may be more beneficial than walking for cardiovascular health in elderly. Methods: A parallel arm, open label, single blind, randomized controlled study was conducted on elderly people with stage-I hypertension aged above 60 years (n=44). Yoga group (n=24) was assigned for yoga practice (includes asanas, pranayama and meditation) and control group (n=20) for brisk-walk for one hour in the morning for 6 days in a week for three months. The outcome measures were cardiovascular indices derived from pulse wave analysis such as left ventricular ejection time (ET), diastolic time (DT) pulse duration (PD), percentage of mean arterial pressure (%MAP), upstroke time (UT), ejection slope (ES), ejection duration index (ED%), pre-ejection period (PEP), and heart rate. Results: The mean within-yoga group change in PD(ms) was -50.29 (CI=-98.5, -2.07; p=0.042), DT(ms): -49.04 (CI=-88.47, -9.61; p=0.017), ED%: 2.107 (CI=0.92, 3.28; p=0.001), HR(bpm): 4.41 (CI=0.43, 8.4; p=0.031), %MAP: 2.08 (CI=0.71, 3.44; p=0.04), ES (mmHg/ms): 14.62 (CI=-3.99, 33.24; p=0.118), ET (ms): -0.66 (CI=11.89, 10.55; p=0.903), UT(ms): -2.54 (CI=14.95, 9.87; p=0.676), PEP (ms): -1.25 (CI=-4.17, 1.67; p=0.11). The mean within-control group change in PD(ms) was 11.15 (CI=-52.26, 74.56; p=0.717), DT(ms): 11.3 (CI=-50.56, 73.16; p=0.706), ED%: -0.101 (CI=-2.7, 2.5; p=0.936), HR (bpm): 0.35 (CI=-4.71, 5.41; p=0.887), %MAP: 0.65 (CI=-1.11, 2.41; p=0.451), ES(mmHg/ms): 0.75 (CI=-15.8, 17.38; p=0.926), ET(ms): 2.2 (CI=-10.5, 14.9; p=0.721), UT(ms): 4.7 (CI=-8.19, 17.59; p=455), PEP (ms): 2.1 (CI=-0.52, 4.72; p=0.11). Analysis of Covariance showed a significant change between-groups in PD (p=0.021), DT (p=0.02), UT (p=0.048), ED% (p=0.049), HR (p=0.036) while no significant difference was observed in ES (p=0.248), ET (p=0.245), PEP (p=0.102) and %MAP (p=0.262). Conclusions: These findings indicate that the yoga practice can induce beneficial changes in cardiovascular function in elderly hypertensive subjects. Further, yoga may be better than walking in improving cardiac health in older individuals.

scholarly journals Improvement of Left Ventricular Ejection Time Measurement in the Impedance Cardiography Combined with the Reflection Photoplethysmography

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 3036 ◽  
Author(s):  
Shing-Hong Liu ◽  
Jia-Jung Wang ◽  
Chun-Hung Su ◽  
Da-Chuan Cheng
Keyword(s):  
Impedance Cardiography ◽  
Left Ventricular ◽  
Ventricular Ejection ◽  
Left Ventricular Ejection ◽  
Artificial Noise ◽  
Ejection Time ◽  
Left Ventricular Ejection Time ◽  
Noise Interference ◽  
Non Invasive ◽  
Ventricular Ejection Time

Cardiac stroke volume (SV) is an essential hemodynamic indicator that can be used to assess whether the pump function of the heart is normal. Non-invasive SV measurement is currently performed using the impedance cardiography (ICG). In this technology, left ventricular ejection time (LVET) is an important parameter which can be determined from the ICG signals. However, the ICG signals are inherently susceptible to artificial noise interference, which leads to an inaccurate LVET measurement and then yields an error in the calculation of SV. Therefore, the goal of the study was to measure LVETs using both the transmission and reflection photoplethysmography (PPG), and to assess whether the measured LVET was more accurate by the PPG signal than the ICG signal. The LVET measured by the phonocardiography (PCG) was used as the standard for comparing with those by the ICG and PPG. The study recruited ten subjects whose LVETs were simultaneously measured by the ICG using four electrodes, the reflection PPG using neck sensors (PPGneck) and the transmission PPG using finger sensors (PPGfinger). In each subject, ten LVETs were obtained from ten heartbeats selected properly from one-minute recording. The differences of the measured LVETs between the PCG and one of the ICG, PPGneck and PPGfinger were −68.2 ± 148.6 ms, 4.8 ± 86.5 ms and −7.0 ± 107.5 ms, respectively. As compared with the PCG, both the ICG and PPGfinger underestimated but the PPGneck overestimated the LVETs. Furthermore, the measured LVET by the PPGneck was the closest to that by the PCG. Therefore, the PPGneck may be employed to improve the LVET measurement in applying the ICG for continuous monitoring of SV in clinical settings.

Responses of peak ear-pulse derivative to changing left ventricular function

1980 ◽  
Vol 238 (3) ◽  
pp. H355-H359 ◽  
Author(s):  
Y. Nakamura ◽  
B. G. Haffty ◽  
D. H. Spodick ◽  
D. Paladino ◽  
K. Moreau ◽  
...  
Keyword(s):  
Ventricular Function ◽  
Cycle Length ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Ejection Time ◽  
Pressure Derivative ◽  
Left Ventricular Ejection Time ◽  
Ejection Rate ◽  
Ventricular Ejection Time ◽  
Technical Reliability

The ear densitograph displacement pulse derivative (dD/dtear) is the analog of the arterial pressure derivative (dP/dt) and behaves comparably under a variety of cardiocirculatory challenges. Technical reliability and uniform application of the transducer are advantages that make it ideal for intrasubject monitoring. With atrial fibrillation as a model of functional variability in eight subjects, peak dD/dtear (P) tracked echocardiographic stroke volume, ejection fraction, ejection rate, and velocity of circumferential fiber shortening quite closely with the exception of some values in three subjects, two of whom had mitral regurgitation and one paradoxic septal movement. In all subjects, P showed good to excellent correlations with cycle length, preejection period (PEP), LVET (left ventricular ejection time), and PEP/LVET. The method appears to be ideally suited to intrasubject monitoring for changing ventricular function.

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