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Frank Starling

Dmitry Telyshev, Maxim Denisov, Alexander Pugovkin, Sergey Selishchev, Igor Nesterenko
In this work, the study results of an implantable pediatric rotary blood pump (PRBP) are presented. They show the results of the numerical simulation of fluid flow rates in the pump. The determination method of the backflows and stagnation regions is represented. The operating points corresponding to fluid flow rates of 1, 3, and 5 L/min for 75-80 mm Hg pressure head are investigated. The study results have shown that use of the pump in the 1 L/min operating point can potentially lead to the appearance of backflows and stagnation regions...
March 6, 2018: Artificial Organs
Thomas Kampourakis, Saraswathi Ponnam, Malcolm Irving
Hypertrophic cardiomyopathy (HCM) is frequently linked to mutations in the protein components of the myosin-containing thick filaments leading to contractile dysfunction and ultimately heart failure. However, the molecular structure-function relationships that underlie these pathological effects remain largely obscure. Here we chose an example mutation (R58Q) in the myosin regulatory light chain (RLC) that is associated with a severe HCM phenotype and combined the results from a wide range of in vitro and in situ structural and functional studies on isolated protein components, myofibrils and ventricular trabeculae to create an extensive map of structure-function relationships...
February 13, 2018: Journal of Molecular and Cellular Cardiology
Zhijie Wang, Jitandrakumar R Patel, David A Schreier, Timothy A Hacker, Richard L Moss, Naomi C Chesler
Pulmonary arterial hypertension (PAH) is a rapidly fatal disease in which mortality is due to right ventricular (RV) failure. It is unclear whether RV dysfunction initiates at the organ-level or the subcellular-level or both. We hypothesized that chronic pressure overload-induced RV dysfunction begins at the organ level with preserved Frank-Starling mechanism in myocytes. To test this hypothesis, we induced PAH with SUGEN+hypoxia (HySu) in mice and measured RV whole-organ and subcellular functional changes by in vivo pressure-volume measurements and in vitro trabeculae length-tension measurements, respectively at multiple time points for up to 56 days...
January 25, 2018: Journal of Applied Physiology
Erin J Howden, Satyam Sarma, Justin S Lawley, Mildred Opondo, William Cornwell, Douglas Stoller, Marcus A Urey, Beverley Adams-Huet, Benjamin D Levine
Background - Poor fitness in middle age is a risk factor for heart failure, particularly heart failure with a preserved ejection fraction. The development of heart failure with a preserved ejection fraction is likely mediated through increased left ventricular (LV) stiffness, a consequence of sedentary aging. In a prospective, parallel group, randomized controlled trial, we examined the effect of 2 years of supervised highintensity exercise training on LV stiffness. Methods - Sixty-one (48% male) healthy, sedentary, middle-aged participants (53±5 years) were randomly assigned to either 2 years of exercise training (n=34) or attention control (control; n=27)...
January 8, 2018: Circulation
R A Phillips, B E Smith, V M Madigan
Purpose of Review: Adequate oxygen delivery is essential for life, with hypoxia resulting in dysfunction, and ultimately death, of the cells, organs and organism. Blood flow delivers the oxygen bound in the blood, while haemodynamics is the science of blood flow. Stroke volume (SV) is the fundamental unit of blood flow, and reflects the interdependent performance of the heart, the vessels and the autonomic nervous system. However, haemodynamic management remains generally poor and predominantly guided by simple blood pressure observations alone...
2017: Current Anesthesiology Reports
Han-Zhong Feng, Jian-Ping Jin
Genetically modified mice are widely used as experimental models to study human heart function and diseases. However, the fast rate of normal mouse heart at 400-600bpm limits its capacity of assessing kinetic parameters that are important for the physiology and pathophysiology of human heart that beats at a much slower rate (75-180bpm). To extend the value of mouse models, we established a protocol to study ex vivo mouse working hearts at a human-like heart rate. In the presence of 300μM lidocaine to lower pacemaker and conductive activities and prevent arrhythmia, a stable rate of 120-130bpm at 37°C is achieved for ex vivo mouse working hearts...
January 2018: Journal of Molecular and Cellular Cardiology
Hanna Schotola, Samuel T Sossalla, André Renner, Jan Gummert, Bernhard C Danner, Peter Schott, Karl Toischer
AIMS: The Frank-Starling mechanism (rapid response (RR)) and the secondary slow response (SR) are known to contribute to increases contractile performance. The contractility of the heart muscle is influenced by pre-load and after-load. Because of the effect of pre-load vs. after-load on these mechanisms in not completely understood, we studied the effect in isolated muscle strips. METHODS AND RESULTS: Progressive stretch lead to an increase in shortening/force development under isotonic (only pre-load) and isometric conditions (pre- and after-load)...
November 2017: ESC Heart Failure
Kazunori Uemura, Toru Kawada, Can Zheng, Meihua Li, Masaru Sugimachi
BACKGROUND: Hemodynamic resuscitation in septic shock requires aggressive fluid replacement and appropriate use of vasopressors to optimize arterial pressure (AP) and cardiac output (CO). Because responses to these drugs vary between patients and within patient over time, strict monitoring of patient condition and repetitive adjustment of drug dose are required. This task is time and labor consuming, and is associated with poor adherence to resuscitation guidelines. To overcome this issue, we developed a computer-controlled closed-loop drug infusion system for automated hemodynamic resuscitation in septic shock, and evaluated the performance of the system in a canine model of endotoxin shock...
October 23, 2017: BMC Anesthesiology
Vivian C A Koh, Yong Kuen Ho, Michael C Stevens, Robert F Salamonsen, Nigel H Lovell, Einly Lim
Control for dual rotary left ventricular assist devices (LVADs) used as a biventricular assist device (BiVAD) is challenging. If the control system fails, flow imbalance between the systemic and the pulmonary circulations would result, subsequently leading to ventricular suction or pulmonary congestion. With the expectation that advanced control approaches such as model predictive control could address the challenges naturally and effectively, we developed a synergistic first principles model predictive controller (MPC) for the BiVAD...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Evandro M Neto-Neves, Andrea L Frump, Alexandra Vayl, Jeffrey A Kline, Tim Lahm
Although extensively used for the study of left ventricular function, limited experience exists with the isolated heart model in the evaluation of right ventricular (RV) function. In particular, no published experience exists with this tool in sugen/hypoxia-induced pulmonary hypertension (SuHx-PH), a frequently used model of severe and progressive PH We sought to characterize markers of RV contractile and diastolic function in SuHx-PH and to establish their relationship with markers of maladaptive RV remodeling...
October 2017: Physiological Reports
José Guilherme Chaui-Berlinck, Luiz Henrique Alves Monteiro
The Frank-Starling law of the heart is a filling-force mechanism (FFm), a positive relationship between the distension of a ventricular chamber and its force of ejection, and such a mechanism is found across all the studied vertebrate lineages. The functioning of the cardiovascular system is usually described by means of the cardiac and vascular functions, the former related to the contractility of the heart and the latter related to the afterload imposed on the ventricle. The crossing of these functions is the so-called 'operation point', and the FFm is supposed to play a stabilizing role for the short-term variations in the working of the system...
December 1, 2017: Journal of Experimental Biology
Michael George Zaki Ghali
The sympathetic nervous system maintains and regulates arterial pressure and tissue perfusion, via control of cardiac output and vasomotor tone. Sympatho-vascular-mediated increases in blood pressure are effected by arterioloconstriction, which causes an increase in afterload, and/or venoconstriction, which increases venous return, left ventricular preload, and consequently, the force of cardiac contraction via Frank-Starling mechanisms; withdrawal of sympathetic drive elicits reciprocal effects. Spinalization reduces mammalian arterial pressure to 40-50 mm Hg consequent to the elimination of descending medullary pre-sympathetic bulbospinal drive to preganglionic sympathetic fibers in the intermediolateral cell column of the spinal cord...
2017: Journal of Integrative Neuroscience
Nisha Charkoudian
No abstract text is available yet for this article.
October 15, 2017: Journal of Physiology
Gregor Ochsner, Markus J Wilhelm, Raffael Amacher, Anastasios Petrou, Nikola Cesarovic, Silvan Staufert, Barbara Röhrnbauer, Francesco Maisano, Christofer Hierold, Mirko Meboldt, Marianne Schmid Daners
Turbodynamic left ventricular assist devices (LVADs) provide a continuous flow depending on the speed at which the pump is set, and do not adapt to the changing requirements of the patient. The limited adaptation of the pump flow (PF) to the amount of venous return can lead to ventricular suction or overload. Physiologic control may compensate such situations by an automatic adaptation of the PF to the volume status of the left ventricle. We evaluated two physiologic control algorithms in an acute study with eight healthy pigs...
September 2017: ASAIO Journal: a Peer-reviewed Journal of the American Society for Artificial Internal Organs
Sampath K Gollapudi, Sherif M Reda, Murali Chandra
Omecamtiv mecarbil (OM) is a pharmacological agent that augments cardiac contractile function by enhancing myofilament Ca(2+) sensitivity. Given that interventions that increase myofilament Ca(2+) sensitivity have the potential to alter length-dependent activation (LDA) of cardiac myofilaments, we tested the influence of OM on this fundamental property of the heart. This is significant not only because LDA is prominent in cardiac muscle but also because it contributes to the Frank-Starling law, a mechanism by which the heart increases stroke volume in response to an increase in venous return...
August 22, 2017: Biophysical Journal
Barry A Borlaug, Yogesh N V Reddy
No abstract text is available yet for this article.
October 2017: JACC. Cardiovascular Imaging
Antonio Messina, Salvatore M Romano, Eleonora Bonicolini, Davide Colombo, Gianmaria Cammarota, Marco Chiostri, Francesco Della Corte, Paolo Navalesi, Didier Payen, Stefano Romagnoli
BACKGROUND: During a fluid challenge, the changes in cardiac performance and peripheral circulatory tone are closely related to the position of the ventricle on the Frank-Starling curve. Some patients have a good haemodynamic response to a fluid challenge, others hardly any response. The early haemodynamic effects of a fluid challenge could predict the final response before the entire fluid volume has been administered. OBJECTIVE: To assess whether a multivariate logistic regression model, including pulse pressure variation (PPV), cardiac cycle efficiency (CCE), arterial elastance and the difference between the dicrotic pressure and both systolic and mean arterial pressure (SAP - Pdic and MAP - Pdic) can predict cardiac responsiveness early during a fluid challenge in comparison with the standard procedure described elsewhere...
November 2017: European Journal of Anaesthesiology
Lorenzo Marcucci, Takumi Washio, Toshio Yanagida
Recent experimental evidence in skeletal muscle demonstrated the existence of a thick-filament mechanosensing mechanism, acting as a second regulatory system for muscle contraction, in addition to calcium-mediated thin filament regulation. These two systems cooperate to generate force, but the extent to which their interaction is relevant in physiologically contracting muscle was not yet assessed experimentally. Therefore, we included both regulatory mechanisms in a mathematical model of rat trabecula and whole ventricle...
July 17, 2017: Scientific Reports
Teruhiko Imamura, Koichiro Kinugawa
Adaptive servo-ventilation (ASV) is a recently-developed non-invasive therapy that improves the clinical course of heart failure (HF) patients. However, the precise hemodynamic response and predictors of ASV therapy remain uncertain. Overall, 69 patients with New York Heart Association HF class II-IV underwent 10-minute ASV testing along with hemodynamic studies. Among them, 21 (30%) achieved an acute response, which was defined as an increase in the cardiac index (CI) during ASV. ΔLeft ventricular end-diastolic pressure (LVEDP) did not correlate with ΔCI, whereas Δtransmural LVEDP, which was calculated by subtracting right ventricular end-diastolic pressure (RVEDP) from LVEDP, and ΔCI were positively correlated, similar to the ascending limb of Frank-Starling's law (P = 0...
August 3, 2017: International Heart Journal
Hiroki Matsuzoe, Kensuke Matsumoto, Hidekazu Tanaka, Yutaka Hatani, Keiko Hatazawa, Hiroyuki Shimoura, Junichi Ooka, Hiroyuki Sano, Keiko Ryo-Koriyama, Toshiro Shinke, Hirotsugu Yamada, Yutaka Okita, Ken-Ichi Hirata
BACKGROUND: Although aortic valve intervention is recommended for virtually all symptomatic patients with aortic stenosis (AS), how urgently the intervention should be performed remains controversial. The aim of this study was thus to determine whether the preload reserve in response to leg-positive pressure (LPP) maneuver could serve for decision-making for AS patients awaiting aortic valve intervention.Methods and Results:Sixty-eight patients with symptomatic AS, who were referred for aortic valve intervention, were recruited...
November 24, 2017: Circulation Journal: Official Journal of the Japanese Circulation Society
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