Theoretical Modeling on Monitoring Left Ventricle Deformation Using Conformal Piezoelectric Sensors

2019 ◽  
Vol 87 (1) ◽  
Author(s):  
Yangyang Zhang ◽  
Chaofeng Lü ◽  
Bingwei Lu ◽  
Xue Feng ◽  
Ji Wang
Keyword(s):  
Real Time ◽  
Output Voltage ◽  
Piezoelectric Materials ◽  
Heart Function ◽  
Heart Diseases ◽  
Left Ventricular ◽  
Deformation Monitoring ◽  
Volume Data ◽  
Mortality And Morbidity ◽  
Lv Volume

Abstract Left ventricular (LV) volume is a crucial indicator for the assessment of the heart function. However, the current clinical practice cannot be used to monitor the LV volume continuously or warn patients with high risk in time before heart attack occurs in everyday life, resulting in high mortality and morbidity. Here, we theoretically validate the potentiality of a conformal real-time LV deformation-monitoring sensor using piezoelectric materials. The electromechanical relationship between the deformation of the hearts and output voltage signals of the sensors is demonstrated first. End-to-end displacements and deformations of piezoelectric films under cyclic load are derived from the output voltage signals and then compared with experimental values. Then, the real-time LV volumes of a pig and a cow are derived and compared by employing the experimental output voltage signals of the flexible sensor mounted on the LV surface. Finally, by employing the LV volume data of healthy people and patients with various heart diseases in the literature, the theoretical output voltage signals of flexile sensors when mounted on LV surface are calculated and compared. These predicted output voltage signals show significant differences for people with different kinds of cardiac diseases. The results in this study demonstrate that the conformal piezoelectric sensor is fully potential to continuously monitor the cardiac deformation and correspondingly provide timely warning for cardiologists and patients with heart diseases.

scholarly journals Application of feed forward and recurrent neural networks in simulation of left ventricular mechanics

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yaghoub Dabiri ◽  
Alex Van der Velden ◽  
Kevin L. Sack ◽  
Jenny S. Choy ◽  
Julius M. Guccione ◽  
...  
Keyword(s):  
Real Time ◽  
Material Properties ◽  
In Silico ◽  
Prediction Models ◽  
Heart Function ◽  
Active Material ◽  
Experimental Studies ◽  
Left Ventricular ◽  
Feed Forward ◽  
Ventricular Mechanics

AbstractAn understanding of left ventricle (LV) mechanics is fundamental for designing better preventive, diagnostic, and treatment strategies for improved heart function. Because of the costs of clinical and experimental studies to treat and understand heart function, respectively, in-silico models play an important role. Finite element (FE) models, which have been used to create in-silico LV models for different cardiac health and disease conditions, as well as cardiac device design, are time-consuming and require powerful computational resources, which limits their use when real-time results are needed. As an alternative, we sought to use deep learning (DL) for LV in-silico modeling. We used 80 four-chamber heart FE models for feed forward, as well as recurrent neural network (RNN) with long short-term memory (LSTM) models for LV pressure and volume. We used 120 LV-only FE models for training LV stress predictions. The active material properties of the myocardium and time were features for the LV pressure and volume training, and passive material properties and element centroid coordinates were features of the LV stress prediction models. For six test FE models, the DL error for LV volume was 1.599 ± 1.227 ml, and the error for pressure was 1.257 ± 0.488 mmHg; for 20 LV FE test examples, the mean absolute errors were, respectively, 0.179 ± 0.050 for myofiber, 0.049 ± 0.017 for cross-fiber, and 0.039 ± 0.011 kPa for shear stress. After training, the DL runtime was in the order of seconds whereas equivalent FE runtime was in the order of several hours (pressure and volume) or 20 min (stress). We conclude that using DL, LV in-silico simulations can be provided for applications requiring real-time results.

Secondary mitral regurgitation (part 1): volumetric quantification and analysis

Heart ◽  
2017 ◽  
Vol 104 (8) ◽  
pp. 634-638 ◽  
Author(s):  
William H Gaasch ◽  
Theo E Meyer
Keyword(s):  
Mitral Regurgitation ◽  
Left Ventricular ◽  
Volume Data ◽  
Regurgitant Volume ◽  
Optimal Method ◽  
End Diastolic Volume ◽  
Volumetric Quantification ◽  
Secondary Mitral Regurgitation ◽  
Lv Volume ◽  
Secondary Mr

Secondary mitral regurgitation (MR) develops as a consequence of left ventricular (LV) dilatation and dysfunction, which complicates its evaluation and management. The goal of this article is to review the assessment of secondary MR with special emphasis on quantification and analysis of LV volume data. At the present time, the optimal method for making these measurements appears to be cardiac MRI. In severe MR (both primary and secondary), the regurgitant fraction (RF) exceeds 50%, and as a result, the LV end diastolic volume (EDV) is increased. In secondary MR, the ejection fraction is depressed (generally <40%) and despite an RF >50%, the regurgitant volume (RegV) rarely meets the current published criteria for severe MR (>60 mL). The ratio of the RegV to EDV, which is very low in secondary MR, reflects the effect of the RegV on the ventricle and it may be predictive of the fractional change in LV size that can be expected after correction of MR. Accurate measurement of the volumetric parameters is essential to proper management of patients with secondary MR.

Ventricular untwisting: a temporal link between left ventricular relaxation and suction

2008 ◽  
Vol 294 (1) ◽  
pp. H505-H513 ◽  
Author(s):  
Yuichi Notomi ◽  
Zoran B. Popović ◽  
Hirotsugu Yamada ◽  
Don W. Wallick ◽  
Maureen G. Martin ◽  
...  
Keyword(s):  
Diastolic Function ◽  
Repeated Measures ◽  
Left Ventricular ◽  
High Temporal Resolution ◽  
Data Sets ◽  
Volume Data ◽  
Elastic Recoil ◽  
Relaxation Phase ◽  
Intraventricular Pressure Gradients ◽  
Lv Volume

Left ventricular (LV) untwisting starts early during the isovolumic relaxation phase and proceeds throughout the early filling phase, releasing elastic energy stored by the preceding systolic deformation. Data relating untwisting, relaxation, and intraventricular pressure gradients (IVPG), which represent another manifestation of elastic recoil, are sparse. To understand the interaction between LV mechanics and inflow during early diastole, Doppler tissue images (DTI), catheter-derived pressures (apical and basal LV, left atrial, and aortic), and LV volume data were obtained at baseline, during varying pacing modes, and during dobutamine and esmolol infusion in seven closed-chest anesthetized dogs. LV torsion and torsional rate profiles were analyzed from DTI data sets (apical and basal short-axis images) with high temporal resolution (6.5 ± 0.7 ms). Repeated-measures regression models showed moderately strong correlation of peak LV twisting with peak LV untwisting rate ( r = 0.74), as well as correlations of peak LV untwisting rate with the time constant of LV pressure decay (tau, r = −0.66) and IVPG ( r = 0.76, P < 0.0001 for all). In a multivariate analysis, peak LV untwisting rate was an independent predictor of tau and IVPG ( P < 0.0001, for both). The start of LV untwisting coincided with the beginning of relaxation and preceded suction-aided filling resulting from elastic recoil. Untwisting rate may be a useful marker of diastolic function or even serve as a therapeutic target for improving diastolic function.

Length-dependent Regulation of Left Ventricular Function in Coronary Surgery Patients 

1999 ◽  
Vol 91 (2) ◽  
pp. 379-387 ◽  
Author(s):  
Stefan G. De Hert ◽  
Thierry C. Gillebert ◽  
Pieter W. Ten Broecke ◽  
Adriaan C. Moulijn
Keyword(s):  
Systolic Pressure ◽  
Left Ventricular ◽  
Lv Function ◽  
Stroke Work ◽  
Coronary Surgery ◽  
Volume Data ◽  
Load Dependence ◽  
End Diastolic Volume ◽  
Lv Volume ◽  
Underlying Mechanisms

Background Load-dependent impairment of left ventricular (LV) function was observed after leg elevation in a subgroup of coronary surgery patients. The present study investigated underlying mechanisms by comparing hemodynamic effects of an increase in LV systolic pressures with leg elevation to effects of a similar increase in systolic pressures with phenylephrine. Methods The study was performed in patients undergoing elective coronary surgery prior to cardiopulmonary bypass. High-fidelity LV pressure tracings (n = 25) and conductance LV volume data (n = 10) were obtained consecutively during leg elevation and after phenylephrine administration (5 microg/kg). Results Leg elevation resulted in a homogeneous increase in end-diastolic volume. The change in stroke volume (SV), stroke work (SW) and dP/dtmax was variable, with an increase in some patients but no change or a decrease in other patients. For a matched increase in systolic pressures, phenylephrine increased SW and dP/dtmax in all patients with no change in SV. Load dependence of relaxation (slope R of the tau-end-systolic pressure relation) was inversely related for changes in SV, SW, and dP/dtmax with leg elevation but not with phenylephrine. Conclusions The different effects of leg elevation and phenylephrine suggest that the observed decrease in SV, SW, and dP/dtmax with leg elevation in some patients could not be attributed to an impaired contractile response to increased systolic LV pressures. Instead, load-dependent impairment of LV function after leg elevation appeared related to a deficient length-dependent regulation of myocardial function.

Abstract 340: IL-10 And HSCRP Were Predictors For The Attenuation Of Heart Functions In Myocardial Ischemia Swine

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Shuzhen Guo ◽  
Wenjing Chuo ◽  
Yong Wang ◽  
Jianxin Chen ◽  
Juan Wang ◽  
...  
Keyword(s):  
Myocardial Ischemia ◽  
Ejection Fraction ◽  
Sham Group ◽  
Early Stage ◽  
Heart Function ◽  
Heart Diseases ◽  
Left Ventricular ◽  
Enzyme Linked Immunosorbent Assay ◽  
Related Factors ◽  
Heart Functions

Background and Objective: Inflammation was one of the most important pathophysiological processes during myocardial ischemia. However, it is still poorly understood about the possibilities of these pro- or anti-inflammation factors be used as prognostic parameters for subsequent attenuation of heart functions. Methods and Results: Chinese experimental mini swines (25±4 kg) were instrumented with a size-matched Ameroid constrictor on the left anterior descending branch (LAD) under general anesthesia in sterile conditions (N=15). And a sham group (N=6) was included. 4 weeks after thoracotomy, more than 90% occlusion of the LAD was proved by coronary angiography. Early stage of ischemia was found by echocardiography which showed focal ischemia in the anterior wall of left ventricular (from apex to papillary muscle level) and unchanged ejection fraction. Meanwhile, Enzyme-linked immunosorbent assay of serum showed that IL-8 (86.83 ±10.96 vs. 130.3 ±10.94-pg/ml, P =0.0322) and IL-10 (0.9619 ±0.1421 vs. 1.660 ±0.1607-pg/ml, P =0.0111) were dramatically decreased compared to sham group, while no significant changes were found in IL-1 (0.3075 ±0.03558 vs. 0.3045 ±0.057371 -ng/ml, P = 0.9643), IL-6 (307.7 ±27.81 vs. 315.8 ±23.07-pg/ml, P =0.8637), high sensitivity C reactive protein (hsCRP) (12.94 ±1.324 vs. 9.943 ±1.442-ng/ml, P =0.2087) and TNF-a(1.769 ±0.1467 vs. 1.260 ±0.3209-ng/ml, P =0.1121). Furthermore, 8 weeks after thoracotomy, ejection fraction(EF) of myocardial ischemia animals were dramatically attenuated (44.69 ±4.494 vs. 60.60 ±3.420-%, P =0.0428). Subsequent EF (8 weeks postoperation) showed a good linear regression with the IL-10 and hsCRP concentration in the early stage of myocardial ischemia (4 weeks postoperation) (EF= 0.525+ 0.132* IL-10- 0.015* hsCRP, P =0.001) when stepwise regression was performed with all inflammation related factors above as dependent variables. Conclusion: These results demonstrate that lower IL-10 and higher hsCRP in serum may be predictors for the attenuation of heart function caused by myocardial ischemia. Further Clinical trials may help to prove the efficiency of these novel insights of prognosis for ischemia heart diseases.

scholarly journals Echocardiographic Techniques of Deformation Imaging in the Evaluation of Maternal Cardiovascular System in Patients with Complicated Pregnancies

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Silvia Visentin ◽  
Chiara Palermo ◽  
Martina Camerin ◽  
Luciano Daliento ◽  
Denisa Muraru ◽  
...  
Keyword(s):  
Cardiovascular System ◽  
Myocardial Function ◽  
Heart Diseases ◽  
Dimensional Space ◽  
Left Ventricular ◽  
Close Monitoring ◽  
Clinical Value ◽  
Mortality And Morbidity ◽  
Deformation Imaging ◽  
Increased Risk

Cardiovascular diseases (CVD) represent the leading cause of maternal mortality and morbidity. Knowledge of CVD in women is constantly evolving and data are emerging that female-specific risk factors as complications of pregnancy are conditions associated with an increased risk for the long-term development of CVD. Echocardiography is a safe and effective imaging technique indicated in symptomatic or asymptomatic pregnant women with congenital heart diseases who require close monitoring of cardiac function. Deformation imaging is an echocardiographic technique used to assess myocardial function by measuring the actual deformation of the myocardium through the cardiac cycle. Speckle-tracking echocardiography (STE) is a two-dimensional (2D) technique which has been found to be more accurate than tissue Doppler to assess both left ventricular (LV) and right ventricular (RV) myocardial function. The use of 2D STE however might present some technical issues due to the tomographic nature of the technique and the motion in the three-dimensional space of the myocardial speckles. This has promoted the use of 3D STE to track the motion of the speckles in the 3D space. This review will focus on the clinical value of the new echocardiographic techniques of deformation imaging used to assess the maternal cardiovascular system in complicated pregnancies.

scholarly journals Tumor-Induced Cardiac Dysfunction: A Potential Role of ROS

Antioxidants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1299
Author(s):  
Priyanka Karekar ◽  
Haley N. Jensen ◽  
Kathryn L. G. Russart ◽  
Devasena Ponnalagu ◽  
Sarah Seeley ◽  
...  
Keyword(s):  
Cell Growth ◽  
Cardiac Function ◽  
Cancer Patients ◽  
Cardiac Dysfunction ◽  
Heart Function ◽  
Heart Diseases ◽  
The Body ◽  
Cardiac Defects ◽  
Mortality And Morbidity ◽  
Irregular Cell

Cancer and heart diseases are the two leading causes of mortality and morbidity worldwide. Many cancer patients undergo heart-related complications resulting in high incidences of mortality. It is generally hypothesized that cardiac dysfunction in cancer patients occurs due to cardiotoxicity induced by therapeutic agents, used to treat cancers and/or cancer-induced cachexia. However, it is not known if localized tumors or unregulated cell growth systemically affect heart function before treatment, and/or prior to the onset of cachexia, hence, making the heart vulnerable to structural or functional abnormalities in later stages of the disease. We incorporated complementary mouse and Drosophila models to establish if tumor induction indeed causes cardiac defects even before intervention with chemotherapy or onset of cachexia. We focused on one of the key pathways involved in irregular cell growth, the Hippo–Yorkie (Yki), pathway. We used overexpression of the transcriptional co-activator of the Yki signaling pathway to induce cellular overgrowth, and show that Yki overexpression in the eye tissue of Drosophila results in compromised cardiac function. We rescue these cardiac phenotypes using antioxidant treatment, with which we conclude that the Yki induced tumorigenesis causes a systemic increase in ROS affecting cardiac function. Our results show that systemic cardiac dysfunction occurs due to abnormal cellular overgrowth or cancer elsewhere in the body; identification of specific cardiac defects associated with oncogenic pathways can facilitate the possible early diagnosis of cardiac dysfunction.

scholarly journals MEASURES AND INDICES FOR INTRINSIC CHARACTERIZATION OF CARDIAC DYSFUNCTION DURING FILLING AND SYSTOLIC EJECTION

2005 ◽  
Vol 05 (02) ◽  
pp. 307-332 ◽  
Author(s):  
LIANG ZHONG ◽  
DHANJOO N. GHISTA ◽  
E. Y.-K. NG ◽  
SOO TEIK LIM ◽  
SIANG JIN CHUA
Keyword(s):  
Differential Equations ◽  
Heart Diseases ◽  
Aortic Pressure ◽  
Left Ventricular ◽  
Contractile Element ◽  
Diastolic Filling ◽  
Myocardial Stress ◽  
Velocity Relationship ◽  
Lv Volume

The paper discusses the development and application of bioengineering indices for reliable diagnosis of cardiac functional modalities in filling and contraction phases. During diastolic filling, the left-ventricular (LV) volume developed is a response to left-atrium (LV) suction at early rapid filling and LA contraction at late filling. However, in LV ejection, the LV flow-rate and aortic pressure constitute response to LV myocardial stress and intra-LV pressure generation. The differential equations used in the governing of these relationships have been developed. By matching the solutions of these differential equations with the clinical data of LV volume and pressure, we can determine the heart model "differential equations" parameters, as well as the derived indices. These parameters and indices include: compliance and resistance-to-filling for characterizing diastolic-filling function, together with the index of LV contractility (in terms of maximum LV contractile power and stress-velocity relationship for contractile element). By evaluating them, it is possible to diagnose more reliably and differentially heart diseases due to an increase in filling-resistance and contractility abnormalities.

Effects of Rest and Exercise on Cardiac Blood Volume Determinations

1997 ◽  
Vol 36 (08) ◽  
pp. 259-264
Author(s):  
N. Topuzović
Keyword(s):  
Radionuclide Ventriculography ◽  
Left Ventricular ◽  
Peak Exercise ◽  
Volume Determination ◽  
Group I ◽  
Lv Volumes ◽  
Group Ii ◽  
Lv Volume

Summary Aim: The purpose of this study was to investigate the changes in blood activity during rest, exercise and recovery, and to assess its influence on left ventricular (LV) volume determination using the count-based method requiring blood sampling. Methods: Forty-four patients underwent rest-stress radionuclide ventriculography; Tc-99m-human serum albumin was used in 13 patients (Group I), red blood cells was labeled using Tc-99m in 17 patients (Group II) in vivo, and in 14 patients (Group III) by modified in vivo/in vitro method. LV volumes were determined by a count-based method using corrected count rate in blood samples obtained during rest, peak exercise and after recovery. Results: In group I at stress, the blood activity decreased by 12.6 ± 5.4%, p <0.05, as compared to the rest level, and increased by 25.1 ± 6.4%, p <0.001, and 12.8 ± 4.5%, p <0.05, above the resting level in group II and III, respectively. This had profound effects on LV volume determinations if only one rest blood aliquot was used: during exercise, the LV volumes significantly decreased by 22.1 ± 9.6%, p <0.05, in group I, whereas in groups II and III it was significantly overestimated by 32.1 ± 10.3%, p <0.001, and 10.7 ± 6.4%, p <0.05, respectively. The changes in blood activity between stress and recovery were not significantly different for any of the groups. Conclusion: The use of only a single blood sample as volume aliquot at rest in rest-stress studies leads to erroneous estimation of cardiac volumes due to significant changes in blood radioactivity during exercise and recovery.

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