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https://www.readbyqxmd.com/read/29449367/load-independent-systolic-and-diastolic-right-ventricular-function-in-heart-failure-with-preserved-ejection-fraction-as-assessed-by-resting-and-handgrip-exercise-pressure-volume-loops
#1
Karl-Philipp Rommel, Maximilian von Roeder, Christian Oberueck, Konrad Latuscynski, Christian Besler, Stephan Blazek, Thomas Stiermaier, Karl Fengler, Volker Adams, Marcus Sandri, Axel Linke, Gerhard Schuler, Holger Thiele, Philipp Lurz
BACKGROUND: Although systolic right ventricular (RV) dysfunction has been shown to be a potent predictor for adverse outcomes in patients with heart failure with preserved ejection fraction (HFpEF), RV functional abnormalities in the course of the syndrome are not well characterized. We, therefore, sought to assess load-independent and load-dependent systolic and diastolic characteristics of RV function in stable outpatients with HFpEF. METHODS AND RESULTS: We invasively obtained RV and left ventricular pressure-volume loops in 24 HFpEF patients and 9 patients without heart failure symptoms with a conductance catheter during basal conditions and handgrip exercise...
February 2018: Circulation. Heart Failure
https://www.readbyqxmd.com/read/29437172/closed-loop-feedback-control-for-microfluidic-systems-through-automated-capacitive-fluid-height-sensing
#2
L R Soenksen, T Kassis, M Noh, L G Griffith, D L Trumper
Precise fluid height sensing in open-channel microfluidics has long been a desirable feature for a wide range of applications. However, performing accurate measurements of the fluid level in small-scale reservoirs (<1 mL) has proven to be an elusive goal, especially if direct fluid-sensor contact needs to be avoided. In particular, gravity-driven systems used in several microfluidic applications to establish pressure gradients and impose flow remain open-loop and largely unmonitored due to these sensing limitations...
February 13, 2018: Lab on a Chip
https://www.readbyqxmd.com/read/29420355/inotropic-effects-of-nicorandil-on-cardiac-contractility-assessed-by-left-ventricular-pressure-volume-relationship-analyses-in-anesthetized-monkeys
#3
Tomomichi Ishizaka, Yu Yoshimatsu, Yu Maeda, Katsuyoshi Chiba, Kazuhiko Mori
Nicorandil is a representative antianginal drug that has dual properties of a nitrate and adenosine triphosphate-sensitive potassium (KATP) channel agonist; however, its effects on integrated cardiac function have not been fully understood. This study was conducted to clarify the functional, hemodynamic, and electrophysiological effects of nicorandil using ventricular pressure-volume loop analysis in isoflurane-anesthetized monkeys. Nicorandil was given intravenously at therapeutic doses of 0.2 and 2 mg/kg over 10 minutes to cynomolgus monkeys (n = 5) with a pause of 10 minutes between the 2 doses...
February 2018: Journal of Cardiovascular Pharmacology
https://www.readbyqxmd.com/read/29411336/central-sleep-apnea-with-cheyne-stokes-breathing-in-heart-failure-from-research-to-clinical-practice-and-beyond
#4
K Terziyski, A Draganova
Characterized by periodic crescendo-decrescendo pattern of breathing alternating with central apneas, Central sleep apnea (CSA) with Cheyne-Stokes Breathing represents a highly prevalent, yet underdiagnosed comorbidity in chronic heart failure (CHF). A diverse body of evidence demonstrates increased morbidity and mortality in the presence of CSB. CSB has been described in both CHF patients with preserved and reduced ejection fraction, regardless of drug treatment. Risk factors for CSB are older age, male gender, high BMI, atrial fibrillation and hypocapnia...
February 7, 2018: Advances in Experimental Medicine and Biology
https://www.readbyqxmd.com/read/29400533/anomalous-features-in-the-potential-energy-landscape-of-a-waterlike-monatomic-model-with-liquid-and-glass-polymorphism
#5
Gang Sun, Limei Xu, Nicolas Giovambattista
We study the potential energy landscape (PEL) of a waterlike monatomic liquid that exhibits a liquid-liquid phase transition (LLPT) and glass-glass transformation (GGT). We identify two anomalous features of the PEL that give origin to both phenomena. Specifically, during the pressure-induced LLPT and GGT, (i) the inherent structures (IS) energy becomes a concave function of volume, and (ii) the IS pressure exhibits a van der Waals-like loop. We argue that features (i) and (ii) imply that the GGT is a (nonequilibrium) first-order phase transition, analogous to the LLPT...
January 19, 2018: Physical Review Letters
https://www.readbyqxmd.com/read/29394944/windkessel-model-of-hemodynamic-state-supported-by-a-pulsatile-ventricular-assist-device-in-premature-ventricle-contraction
#6
Keun Her, Joon Yeong Kim, Ki Moo Lim, Seong Wook Choi
BACKGROUND: Counter-pulsation control (CPC) by ventricular assist devices (VADs) is believed to reduce cardiac load and increase coronary perfusion. However, patients with VADs have a higher risk of arrhythmia, which may cause the CPC to fail. Consequently, CPC has not been applied by VADs in clinical practice. The phase-locked loop (PLL) algorithm for CPC is readily implemented in VADs; however, it requires a normal, consistent heartbeat for adequate performance. When an arrhythmia occurs, the algorithm maintains a constant pumping rate despite the unstable heartbeat...
February 2, 2018: Biomedical Engineering Online
https://www.readbyqxmd.com/read/29365118/initial-in-vitro-testing-of-a-paediatric-continuous-flow-total-artificial-heart
#7
Kiyotaka Fukamachi, Jamshid H Karimov, David J Horvath, Gengo Sunagawa, Nicole A Byram, Barry D Kuban, Nader Moazami
OBJECTIVES: Mechanical circulatory support has become standard therapy for adult patients with end-stage heart failure; however, in paediatric patients with congenital heart disease, the options for chronic mechanical circulatory support are limited to paracorporeal devices or off-label use of devices intended for implantation in adults. Congenital heart disease and cardiomyopathy often involve both the left and right ventricles; in such cases, heart transplantation, a biventricular assist device or a total artificial heart is needed to adequately sustain both pulmonary and systemic circulations...
January 19, 2018: Interactive Cardiovascular and Thoracic Surgery
https://www.readbyqxmd.com/read/29350681/aav-9-mediated-phosphatase-1-inhibitor-1-overexpression-improves-cardiac-contractility-in-unchallenged-mice-but-is-deleterious-in-pressure-overload
#8
D M Schwab, L Tilemann, R Bauer, M Heckmann, A Jungmann, M Wagner, J Burgis, C Vettel, H A Katus, A El-Armouche, O J Müller
The downregulation of β-adrenergic receptors (β-AR) and decreased cAMP-dependent protein kinase activity in failing hearts results in decreased phosphorylation and inactivation of phosphatase-inhibitor-1 (I-1), a distal amplifier element of β-adrenergic signaling, leading to increased protein phosphatase 1 activity and dephosphorylation of key phosphoproteins, including phospholamban. Downregulated and hypophosphorylated I-1 likely contributes to β-AR desensitization; therefore its modulation is a promising approach in heart failure treatment...
January 2018: Gene Therapy
https://www.readbyqxmd.com/read/29330837/computer-simulated-modeling-of-healthy-and-diseased-right-ventricular-and-pulmonary-circulation
#9
Jody Chou, Joseph B Rinehart
We have previously developed a simulated cardiovascular physiology model for in-silico testing and validation of novel closed-loop controllers. To date, a detailed model of the right heart and pulmonary circulation was not needed, as previous controllers were not intended for use in patients with cardiac or pulmonary pathology. With new development of controllers for vasopressors, and looking forward, for combined vasopressor-fluid controllers, modeling of right-sided and pulmonary pathology is now relevant to further in-silico validation, so we aimed to expand our existing simulation platform to include these elements...
January 12, 2018: Journal of Clinical Monitoring and Computing
https://www.readbyqxmd.com/read/29310997/neurohormonal-imbalance-a-neglected-problem-and-potential-therapeutic-target-in-acute-heart-failure
#10
Steven R Goldsmith, Bradley A Bart, Ileana L Piña
Decompensated or acute heart failure (AHF) is characterized by increased ventricular and atrial pressures which may lead to and be caused by circulatory congestion. Unless due to a primary decrease in cardiac function, congestion arises from volume expansion or vasoconstriction. In turn, volume expansion and vasoconstriction are due to neurohormonal imbalance since both result from activation of the sympathetic nervous system, the renin-angiotensin-aldosterone axis and excess secretion of arginine vasopressin...
December 16, 2017: Current Problems in Cardiology
https://www.readbyqxmd.com/read/29297912/temperature-change-rate-actuated-bubble-mixing-for-homogeneous-rehydration-of-dry-pre-stored-reagents-in-centrifugal-microfluidics
#11
S Hin, N Paust, M Keller, M Rombach, O Strohmeier, R Zengerle, K Mitsakakis
In centrifugal microfluidics, dead volumes in valves downstream of mixing chambers can hardly be avoided. These dead volumes are excluded from mixing processes and hence cause a concentration gradient. Here we present a new bubble mixing concept which avoids such dead volumes. The mixing concept employs heating to create a temperature change rate (TCR) induced overpressure in the air volume downstream of mixing chambers. The main feature is an air vent with a high fluidic resistance, representing a low pass filter with respect to pressure changes...
January 3, 2018: Lab on a Chip
https://www.readbyqxmd.com/read/29288156/left-ventricular-torsion-shear-angle-volume-approach-for-noninvasive-evaluation-of-diastolic-dysfunction-in-preserved-ejection-fraction
#12
Oleg F Sharifov, Chun G Schiros, Inmaculada Aban, Gilbert J Perry, Louis J Dell'italia, Steven G Lloyd, Thomas S Denney, Himanshu Gupta
BACKGROUND: Accurate noninvasive diagnostic tools for evaluating left ventricular (LV) diastolic dysfunction (LVDD) are limited in preserved LV ejection fraction. We previously proposed the relationship of normalized rate of change in LV torsion shear angle (φ') to corresponding rate of change in LV volume (V') during early diastole (represented as -dφ'/dV') as a measure of LV diastolic function. We prospectively evaluated diagnostic accuracy of -dφ'/dV' in respect to invasive LV parameters...
December 29, 2017: Journal of the American Heart Association
https://www.readbyqxmd.com/read/29246513/value-of-myocardial-work-estimation-in-the-prediction-of-response-to-cardiac-resynchronization-therapy
#13
Elena Galli, Christophe Leclercq, Maxime Fournet, Arnaud Hubert, Anne Bernard, Otto A Smiseth, Philippe Mabo, Eigil Samset, Alfredo Hernandez, Erwan Donal
BACKGROUND: Cardiac resynchronization therapy (CRT) in heart failure is plagued by too many nonresponders. The aim of the present study is to evaluate whether the estimation of myocardial performance by pressure-strain loops (PSLs) is useful for the selection of CRT candidates. METHODS: Ninety-seven patients undergoing CRT were included in the study. Bidimensional and speckle-tracking echocardiography were performed before CRT and at the 6-month follow-up (FU). Conventional dyssynchrony parameters were evaluated...
December 12, 2017: Journal of the American Society of Echocardiography
https://www.readbyqxmd.com/read/29246510/echocardiographic-detection-of-increased-ventricular-diastolic-stiffness-in-pediatric-heart-transplant-recipients-a-pilot-study
#14
Shahryar M Chowdhury, Ryan J Butts, Anthony M Hlavacek, Carolyn L Taylor, Karen S Chessa, Varsha M Bandisode, Girish S Shirali, Arni Nutting, G Hamilton Baker
BACKGROUND: Pediatric heart transplant recipients are at risk for increased left ventricular (LV) diastolic stiffness. However, the noninvasive evaluation of LV stiffness has remained elusive in this population. The objective of this study was to compare novel echocardiographic measures of LV diastolic stiffness versus gold-standard measures derived from pressure-volume loop (PVL) analysis in pediatric heart transplant recipients. METHODS: Patients undergoing left heart catheterization were prospectively enrolled...
December 12, 2017: Journal of the American Society of Echocardiography
https://www.readbyqxmd.com/read/29236087/fiber-fabry-perot-force-sensor-with-small-volume-and-high-performance-for-assessing-fretting-damage-of-steam-generator-tubes
#15
Peijian Huang, Ning Wang, Junying Li, Yong Zhu, Jie Zhang
Measuring the radial collision force between the steam generator tube (SGT) and the tube support plate (TSP) is essential to assess the fretting damage of the SGT. In order to measure the radial collision force, a novel miniaturized force sensor based on fiber Fabry-Perot (F-P) was designed, and the principle and characteristics of the sensor were analyzed in detail. Then, the F-P force sensor was successfully fabricated and calibrated, and the overall dimensions of the encapsulated fiber F-P sensor were 17 mm × 5 mm × 3 mm (L × W × H)...
December 13, 2017: Sensors
https://www.readbyqxmd.com/read/29208771/advanced-iron-overload-cardiomyopathy-in-a-genetic-murine-model-is-rescued-by-resveratrol-therapy
#16
Subhash K Das, Pavel Zhabyeyev, Ratnadeep Basu, Vaibhav B Patel, Jason R B Dyck, Zamaneh Kassiri, Gavin Y Oudit
Iron-overload cardiomyopathy is prevalent on a worldwide basis and is a major co-morbidity in patients with genetic hemochromatosis and secondary iron overload. Therapies are limited in part due to lack of a valid pre-clinical model, which recapitulates advanced iron-overload cardiomyopathy. Male hemojuvelin knockout (HJVKO) mice, which lack hemojuvelin (HJV), a bone morphogenetic co-receptor protein required for hepcidin expression and systemic iron homeostasis, were fed a high iron diet starting at 4 weeks of age for a duration of 1 year...
December 5, 2017: Bioscience Reports
https://www.readbyqxmd.com/read/29193495/premature-birth-affects-the-degree-of-airway-dysanapsis-and-mechanical-ventilatory-constraints
#17
Joseph W Duke, Igor M Gladstone, A William Sheel, Andrew T Lovering
What is the central question of this study? Adult survivors of preterm birth without (PRE) and with bronchopulmonary dysplasia (BPD) have airflow obstruction at rest and significant mechanical ventilatory constraints during exercise compared with those born at full term (CON). Do PRE/BPD have smaller airways, indexed via the dysanapsis ratio, than CON? What is the main finding and its importance? The dysanapsis ratio was significantly smaller in BPD and PRE compared with CON, with BPD having the smallest dysanapsis ratio...
February 1, 2018: Experimental Physiology
https://www.readbyqxmd.com/read/29190612/assessment-of-bronchial-obstruction-using-lateral-pressure-measurement-during-bronchoscopy
#18
Hiroki Nishine, Takehiko Hiramoto, Takeo Inoue, Naoki Furuya, Hirotaka Kida, Hiroshi Handa, Seiichi Nobuyama, Masamichi Mineshita, Teruomi Miyazawa
BACKGROUND: In patients with bronchial obstruction estimating the location of the maximal obstruction is crucial for guiding interventional bronchoscopy. However, flow-volume curves cannot discriminate between the right and left lungs. OBJECTIVES: The aim of this study was to physiologically evaluate bronchial obstruction during interventional bronchoscopy. METHODS: We prospectively measured lateral airway pressure (Plat) at either side of the obstruction using a double-lumen catheter (pressure-pressure [P-P] curve) simultaneously to assess the degree of bronchial obstruction in 22 patients...
November 30, 2017: Respiration; International Review of Thoracic Diseases
https://www.readbyqxmd.com/read/29163841/assessing-right-ventricular-function-in-pulmonary-hypertension-patients-and-the-correlation-with-the-new-york-heart-association-nyha-classification
#19
Xiaoke Shang, Shuna Xiao, Nianguo Dong, Rong Lu, Lijun Wang, Bin Wang, Yousan Chen, Liang Zhong, Mei Liu
This investigation aimed to compare the pressure-volume loop (PV loop) measurements in three less symptomatic categories (New York Heart Association classes , NYHA I, II, and III) of pulmonary hypertension (PH) patients since NYHA classification system performance is limited by the shortcomings discussed above. Thirty-six patients were enrolled in this study with PV loop measurement acquisition via micro-conductance catheters. Functional classification according to NYHA was determined with comprehensive assessing function and activity...
October 27, 2017: Oncotarget
https://www.readbyqxmd.com/read/29153929/accuracy-of-a-simulation-algorithm-for-modelling-lv-contractility-diastolic-capacitance-and-energetics-using-data-available-from-common-hemodynamic-monitors-and-echocardiography
#20
Paul M Heerdt, Scott Korfhagen, Hesham Ezz, Clara Oromendia
OBJECTIVE: To test the hypothesis that a simulation algorithm populated with data readily available from hemodynamic monitors and echocardiography can accurately model cardiac contractility, diastolic capacitance, and energetics. DESIGN: Bland-Altman analysis of paired data sets. SETTING: University laboratory. PARTICIPANTS: Archived data previously recorded from 7 anesthetized swine. MEASUREMENTS AND MAIN RESULTS: Left ventricular pressure and volume (LVV) data that had been continuously recorded over a range of inotropic conditions were used as reference data...
September 27, 2017: Journal of Cardiothoracic and Vascular Anesthesia
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