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Frank Starling

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https://www.readbyqxmd.com/read/28639137/the-frank-starling-law-a-jigsaw-of-titin-proportions
#1
REVIEW
Vasco Sequeira, Jolanda van der Velden
The Frank-Starling Law dictates that the heart is able to match ejection to the dynamic changes occurring during cardiac filling, hence efficiently regulating isovolumetric contraction and shortening. In the last four decades, efforts have been made to identify a common fundamental basis for the Frank-Starling heart that can explain the direct relationship between muscle lengthening and its increased sensitization to Ca(2+). The term 'myofilament length-dependent activation' describes the length-dependent properties of the myofilaments, but what is(are) the underlying molecular mechanism(s) is a matter of ongoing debate...
June 21, 2017: Biophysical Reviews
https://www.readbyqxmd.com/read/28571718/effects-of-simulated-ischemia-on-the-transmural-differences-in-the-frank-starling-relationship-in-isolated-mouse-ventricular-cardiomyocytes
#2
REVIEW
Anastasia Khokhlova, Gentaro Iribe, Yohei Yamaguchi, Keiji Naruse, Olga Solovyova
The electrical and mechanical functions of cardiomyocytes differ in relation to the spatial locations of cells in the ventricular wall. This physiological heterogeneity may change under pathophysiological conditions, providing substrates for arrhythmia and contractile dysfunctions. Previous studies have reported distinctions in the electrophysiological and mechanical responses to ischemia of unloaded subendocardial (ENDO) and subepicardial (EPI) single cardiomyocytes. In this paper, we briefly recapitulated the available experimental data on the ischemia effects on the transmural cellular gradient in the heart ventricles and for the first time evaluated the preload-dependent changes in passive and active forces in ENDO and EPI cardiomyocytes isolated from mouse hearts subjected to simulated ischemia...
May 29, 2017: Progress in Biophysics and Molecular Biology
https://www.readbyqxmd.com/read/28543923/sex-differences-in-fitness-and-cardiac-function-during-exercise-in-adolescents-with-chronic-fatigue
#3
Paolo T Pianosi, Eric Emerling, Kristin C Mara, Amy L Weaver, Philip R Fischer
Females demonstrate less robust Frank-Starling mechanism with respect to cardiac preload than males at rest. We asked whether this phenomenon would also affect cardiac performance during exercise. We hypothesized that stroke volume (SV) response to exercise would be more limited in deconditioned females such that cardiac output would be mainly rate dependent, compared with males. We conducted a chart audit of clinical exercise tests performed by adolescents with chronic fatigue. Oxygen uptake (VO2 ) was measured breath-by-breath at rest and during cycle ergometry, while cardiac output was measured by acetylene rebreathing at rest plus 2-3 sub-threshold workloads...
May 24, 2017: Scandinavian Journal of Medicine & Science in Sports
https://www.readbyqxmd.com/read/28515459/associations-between-left-ventricular-cavity-size-and-cardiac-function-and-overload-determined-by-natriuretic-peptide-levels-and-a-covariance-structure-analysis
#4
Jun Yoshida, Makoto Kawai, Kosuke Minai, Kazuo Ogawa, Takayuki Ogawa, Michihiro Yoshimura
The effects of left ventricular (LV) cavity size on cardiac function and overload have not yet been fully elucidated. We performed a covariance structure analysis and drew theoretical path models to clarify the effects of hemodynamic parameters on the stroke volume index (SVI) as a marker of cardiac function and on the plasma B-type natriuretic peptide (BNP) level as a marker of cardiac overload. We simultaneously measured various hemodynamic parameters and the BNP levels during cardiac catheterization in 1,715 inpatients of our institution...
May 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28471573/immunity-life-and-dancing-starlings-a-physician-s-perspective
#5
Dani Bercovich, Geoffrey Goodman, M Eric Gershwin
Immune function is the most basic physiological process in humans and indeed throughout the animal kingdom. Interestingly, the vast majority of textbooks of physiology do not include a chapter on immunity. Our species survival is dependent on the diversity of the immune response and the ability for antigen presentation and effector mechanisms to be enormously promiscuous. As physicians, we are likely all too aware of how brief our life span is and the myriad of diseases and events that shorten it. It is not surprising that we question where our life comes from and our relationship within the universe...
August 2016: Israel Medical Association Journal: IMAJ
https://www.readbyqxmd.com/read/28459742/clinical-implications-of-physiologic-flow-adjustment-in-continuous-flow-left-ventricular-assist-devices
#6
Vakhtang Tchantchaleishvili, Jessica G Y Luc, Caitlin M Cohan, Kevin Phan, Laila Hübbert, Steven W Day, H Todd Massey
There is increasing evidence for successful management of end-stage heart failure with continuous-flow left ventricular assist device (CF-LVAD) technology. However, passive flow adjustment at fixed CF-LVAD speed is susceptible to flow balancing issues as well as adverse hemodynamic effects relating to the diminished arterial pulse pressure and flow. With current therapy, flow cannot be adjusted with changes in venous return, which can vary significantly with volume status. This limits the performance and safety of CF-LVAD...
May 2017: ASAIO Journal: a Peer-reviewed Journal of the American Society for Artificial Internal Organs
https://www.readbyqxmd.com/read/28448528/minimally-invasive-estimation-of-ventricular-dead-space-volume-through-use-of-frank-starling-curves
#7
Shaun Davidson, Chris Pretty, Antoine Pironet, Thomas Desaive, Nathalie Janssen, Bernard Lambermont, Philippe Morimont, J Geoffrey Chase
This paper develops a means of more easily and less invasively estimating ventricular dead space volume (Vd), an important, but difficult to measure physiological parameter. Vd represents a subject and condition dependent portion of measured ventricular volume that is not actively participating in ventricular function. It is employed in models based on the time varying elastance concept, which see widespread use in haemodynamic studies, and may have direct diagnostic use. The proposed method involves linear extrapolation of a Frank-Starling curve (stroke volume vs end-diastolic volume) and its end-systolic equivalent (stroke volume vs end-systolic volume), developed across normal clinical procedures such as recruitment manoeuvres, to their point of intersection with the y-axis (where stroke volume is 0) to determine Vd...
2017: PloS One
https://www.readbyqxmd.com/read/28434968/cardiac-contractility-correction-strategies-applied-to-telemetry-data-from-a-hesi-sponsored-consortium
#8
Emmanuel Boulay, Michael K Pugsley, Vincent Jacquemet, Alain Vinet, Michael V Accardi, Maxim Soloviev, Eric Troncy, Jennifer M Doyle, Jennifer Beck Pierson, Simon Authier
INTRODUCTION: QT has a long history of heart rate (HR) correction but limited investigations have been undertaken to assess the impact of cardiovascular parameters on left ventricular (LV) contractility in drug safety testing. Cardiac contractility is affected by preload (Cyon-Frank-Starling law), afterload (Anrep effect) and HR (Bowditch effect). We evaluated multi-parameter correction methods to help with dP/dtmax interpretation. METHODOLOGY: Modeling was undertaken using data from dogs in single or double 4×4 Latin square studies...
April 20, 2017: Journal of Pharmacological and Toxicological Methods
https://www.readbyqxmd.com/read/28397830/cardiac-kinematic-parameters-computed-from-video-of-in-situ-beating-heart
#9
Lorenzo Fassina, Giacomo Rozzi, Stefano Rossi, Simone Scacchi, Maricla Galetti, Francesco Paolo Lo Muzio, Fabrizio Del Bianco, Piero Colli Franzone, Giuseppe Petrilli, Giuseppe Faggian, Michele Miragoli
Mechanical function of the heart during open-chest cardiac surgery is exclusively monitored by echocardiographic techniques. However, little is known about local kinematics, particularly for the reperfused regions after ischemic events. We report a novel imaging modality, which extracts local and global kinematic parameters from videos of in situ beating hearts, displaying live video cardiograms of the contraction events. A custom algorithm tracked the movement of a video marker positioned ad hoc onto a selected area and analyzed, during the entire recording, the contraction trajectory, displacement, velocity, acceleration, kinetic energy and force...
April 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28343262/cavin-1-deficiency-modifies-myocardial-and-coronary-function-stretch-responses-and-ischaemic-tolerance-roles-of-nos-over-activity
#10
Mika Kaakinen, Melissa E Reichelt, Zhibin Ma, Charles Ferguson, Nick Martel, Enzo R Porrello, James E Hudson, Walter G Thomas, Robert G Parton, John P Headrick
Caveolae and associated cavin and caveolins may govern myocardial function, together with responses to mechanical and ischaemic stresses. Abnormalities in these proteins are also implicated in different cardiovascular disorders. However, specific roles of the cavin-1 protein in cardiac and coronary responses to mechanical/metabolic perturbation remain unclear. We characterised cardiovascular impacts of cavin-1 deficiency, comparing myocardial and coronary phenotypes and responses to stretch and ischaemia-reperfusion in hearts from cavin-1 (+/+) and cavin-1 (-/-) mice...
May 2017: Basic Research in Cardiology
https://www.readbyqxmd.com/read/28265101/myosin-filament-activation-in-the-heart-is-tuned-to-the-mechanical-task
#11
Massimo Reconditi, Marco Caremani, Francesca Pinzauti, Joseph D Powers, Theyencheri Narayanan, Ger J M Stienen, Marco Linari, Vincenzo Lombardi, Gabriella Piazzesi
The mammalian heart pumps blood through the vessels, maintaining the dynamic equilibrium in a circulatory system driven by two pumps in series. This vital function is based on the fine-tuning of cardiac performance by the Frank-Starling mechanism that relates the pressure exerted by the contracting ventricle (end systolic pressure) to its volume (end systolic volume). At the level of the sarcomere, the structural unit of the cardiac myocytes, the Frank-Starling mechanism consists of the increase in active force with the increase of sarcomere length (length-dependent activation)...
March 21, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28236865/does-fasting-influence-preload-responsiveness-in-asa-1-and-2-volunteers
#12
Daniel Rodrigues Alves, Regina Ribeiras
INTRODUCTION: Preoperative fasting was long regarded as an important cause of fluid depletion, leading to hemodynamic instability during surgery should replenishment is not promptly instituted. Lately, this traditional point of view has been progressively challenged, and a growing number of authors now propose a more restrictive approach to fluid management, although doubt remains as to the true hemodynamic influence of preoperative fasting. METHODS: We designed an observational, analytic, prospective, longitudinal study in which 31 ASA 1 and ASA 2 volunteers underwent an echocardiographic examination both before and after a fasting period of at least 6hours (h)...
March 2017: Brazilian Journal of Anesthesiology
https://www.readbyqxmd.com/read/28229860/distinct-contributions-of-the-thin-and-thick-filaments-to-length-dependent-activation-in-heart-muscle
#13
Xuemeng Zhang, Thomas Kampourakis, Ziqian Yan, Ivanka Sevrieva, Malcolm Irving, Yin-Biao Sun
The Frank-Starling relation is a fundamental auto-regulatory property of the heart that ensures the volume of blood ejected in each heartbeat is matched to the extent of venous filling. At the cellular level, heart muscle cells generate higher force when stretched, but despite intense efforts the underlying molecular mechanism remains unknown. We applied a fluorescence-based method, which reports structural changes separately in the thick and thin filaments of rat cardiac muscle, to elucidate that mechanism...
February 23, 2017: ELife
https://www.readbyqxmd.com/read/28223172/a-simple-model-of-cardiac-muscle-for-multiscale-simulation-passive-mechanics-crossbridge-kinetics-and-calcium-regulation
#14
Fyodor A Syomin, Andrey K Tsaturyan
A simple model of cardiac muscle was designed for multiscale simulation of heart mechanics. Relaxed cardiac muscle was described as a transversally isotropic hyperelastic material. Active tension caused by actin-myosin crossbridges depends on the ensemble averaged strain of myosin heads bound to actin. Calcium activation was modeled by Ca(2+) binding to troponin-C. To account for the dependence of troponin affinity for Ca(2+) on myosin heads strongly bound to actin, the kinetics of troponin binding to Ca(2+) in the overlap zone of the thin and thick filaments and outside it were separated...
February 20, 2017: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/28212239/the-frank-starling-curve-is-not-equivalent-to-the-fluid-responsiveness-curve
#15
Ubbo Frank Wiersema, Shailesh Bihari
No abstract text is available yet for this article.
March 2017: Critical Care Medicine
https://www.readbyqxmd.com/read/28188931/percutaneous-left-atrial-appendage-closure-improves-left-atrial-mechanical-function-through-frank-starling-mechanism
#16
Augustin Coisne, Rosario Pilato, François Brigadeau, Didier Klug, Christelle Marquie, Zouheir Souissi, Marjorie Richardson, Stéphanie Mouton, Anne-Sophie Polge, Patrizio Lancellotti, Dominique Lacroix, David Montaigne
BACKGROUND: Modifications in left atrial (LA) flow velocities after left atrial appendage (LAA) exclusion have been shown in animal and ex vivo models. In a substudy of PROTECT AF (Percutaneous Closure of the Left Atrial Appendage Versus Warfarin Therapy for Prevention of Stroke in Patients With Atrial Fibrillation), an objective improvement in quality of life was observed after LAA closure. OBJECTIVE: The purpose of this study was to investigate the impact of LAA closure on LA transport function...
May 2017: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/28140353/basic-cardiovascular-variability-signals-mutual-directed-interactions-explored-in-the-information-domain
#17
Michal Javorka, Jana Krohova, Barbora Czippelova, Zuzana Turianikova, Zuzana Lazarova, Kamil Javorka, Luca Faes
The study of short-term cardiovascular interactions is classically performed through the bivariate analysis of the interactions between the beat-to-beat variability of heart period (RR interval from the ECG) and systolic blood pressure (SBP). Recent progress in the development of multivariate time series analysis methods is making it possible to explore how directed interactions between two signals change in the context of networks including other coupled signals. Exploiting these advances, the present study aims at assessing directional cardiovascular interactions among the basic variability signals of RR, SBP and diastolic blood pressure (DBP), using an approach which allows direct comparison between bivariate and multivariate coupling measures...
May 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28098356/mechano-chemo-transduction-in-cardiac-myocytes
#18
Ye Chen-Izu, Leighton T Izu
The heart has the ability to adjust to changing mechanical loads. The Frank-Starling law and the Anrep effect describe exquisite intrinsic mechanisms the heart has for autoregulating the force of contraction to maintain cardiac output under changes of preload and afterload. Although these mechanisms have been known for more than a century, their cellular and molecular underpinnings are still debated. How does the cardiac myocyte sense changes in preload or afterload? How does the myocyte adjust its response to compensate for such changes? In cardiac myocytes Ca(2+) is a crucial regulator of contractile force and in this review we compare and contrast recent studies from different labs that address these two important questions...
June 15, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28040236/-does-fasting-influence-preload-responsiveness-in-asa-1-and-2-volunteers
#19
Daniel Rodrigues Alves, Regina Ribeiras
INTRODUCTION: Preoperative fasting was long regarded as an important cause of fluid depletion, leading to hemodynamic instability during surgery should replenishment not be promptly instituted. Lately, this traditional point of view has been progressively challenged, and a growing number of authors now propose a more restrictive approach to fluid management, although doubt remains as to the true hemodynamic influence of preoperative fasting. METHODS: We designed an observational, analytic, prospective, longitudinal study in which 31 ASA 1 and ASA 2 volunteers underwent an echocardiographic examination both before and after a fasting period of at least 6h...
March 2017: Revista Brasileira de Anestesiologia
https://www.readbyqxmd.com/read/28034373/body-weight-change-during-and-after%C3%A2-hospitalization-for-acute-heart%C3%A2-failure-%C3%A2-patient-characteristics-markers-of-congestion-and-outcomes-findings-from-the-ascend-hf-trial
#20
Andrew P Ambrosy, Lukasz P Cerbin, Paul W Armstrong, Javed Butler, Adrian Coles, Adam D DeVore, Mark E Dunlap, Justin A Ezekowitz, G Michael Felker, Marat Fudim, Stephen J Greene, Adrian F Hernandez, Christopher M O'Connor, Philip Schulte, Randall C Starling, John R Teerlink, Adriaan A Voors, Robert J Mentz
OBJECTIVES: This study sought to examine the relationships between in-hospital and post-discharge body weight changes and outcomes among patients hospitalized for acute heart failure (AHF). BACKGROUND: Body weight changes during and after hospitalization for AHF and the relationships with outcomes have not been well characterized. METHODS: A post hoc analysis was performed of the ASCEND-HF (Acute Study of Clinical Effectiveness of Nesiritide and Decompensated Heart Failure) trial, which enrolled patients admitted for AHF regardless of ejection fraction...
January 2017: JACC. Heart Failure
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