1
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Bronicki RA, Tume S, Gomez H, Dezfulian C, Penny DJ, Pinsky MR, Burkhoff D. Application of Cardiovascular Physiology to the Critically Ill Patient. Crit Care Med 2024; 52:821-832. [PMID: 38126845 DOI: 10.1097/ccm.0000000000006136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
OBJECTIVES To use the ventricular pressure-volume relationship and time-varying elastance model to provide a foundation for understanding cardiovascular physiology and pathophysiology, interpreting advanced hemodynamic monitoring, and for illustrating the physiologic basis and hemodynamic effects of therapeutic interventions. We will build on this foundation by using a cardiovascular simulator to illustrate the application of these principles in the care of patients with severe sepsis, cardiogenic shock, and acute mechanical circulatory support. DATA SOURCES Publications relevant to the discussion of the time-varying elastance model, cardiogenic shock, and sepsis were retrieved from MEDLINE. Supporting evidence was also retrieved from MEDLINE when indicated. STUDY SELECTION, DATA EXTRACTION, AND SYNTHESIS Data from relevant publications were reviewed and applied as indicated. CONCLUSIONS The ventricular pressure-volume relationship and time-varying elastance model provide a foundation for understanding cardiovascular physiology and pathophysiology. We have built on this foundation by using a cardiovascular simulator to illustrate the application of these important principles and have demonstrated how complex pathophysiologic abnormalities alter clinical parameters used by the clinician at the bedside.
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Affiliation(s)
- Ronald A Bronicki
- Division of Pediatric Critical Care Medicine, Department of Pediatrics, Baylor College of Medicine, Texas Children's Hospital, Houston, TX
| | - Sebastian Tume
- Division of Pediatric Critical Care Medicine, Department of Pediatrics, Baylor College of Medicine, Texas Children's Hospital, Houston, TX
| | - Hernando Gomez
- Critical Care Medicine Department, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Cameron Dezfulian
- Division of Pediatric Critical Care Medicine, Department of Pediatrics, Baylor College of Medicine, Texas Children's Hospital, Houston, TX
| | - Daniel J Penny
- Division of Pediatric Cardiology, Department of Pediatrics, Baylor College of Medicine, Texas Children's Hospital, Houston, TX
| | - Michael R Pinsky
- Critical Care Medicine Department, University of Pittsburgh School of Medicine, Pittsburgh, PA
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2
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Usui Y, Hanashima A, Hashimoto K, Kimoto M, Ohira M, Mohri S. Comparative analysis of ventricular stiffness across species. Physiol Rep 2024; 12:e16013. [PMID: 38644486 PMCID: PMC11033294 DOI: 10.14814/phy2.16013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 04/01/2024] [Accepted: 04/01/2024] [Indexed: 04/23/2024] Open
Abstract
Investigating ventricular diastolic properties is crucial for understanding the physiological cardiac functions in organisms and unraveling the pathological mechanisms of cardiovascular disorders. Ventricular stiffness, a fundamental parameter that defines ventricular diastolic functions in chordates, is typically analyzed using the end-diastolic pressure-volume relationship (EDPVR). However, comparing ventricular stiffness accurately across chambers of varying maximum volume capacities has been a long-standing challenge. As one of the solutions to this problem, we propose calculating a relative ventricular stiffness index by applying an exponential approximation formula to the EDPVR plot data of the relationship between ventricular pressure and values of normalized ventricular volume by the ventricular weight. This article reviews the potential, utility, and limitations of using normalized EDPVR analysis in recent studies. Herein, we measured and ranked ventricular stiffness in differently sized and shaped chambers using ex vivo ventricular pressure-volume analysis data from four animals: Wistar rats, red-eared slider turtles, masu salmon, and cherry salmon. Furthermore, we have discussed the mechanical effects of intracellular and extracellular viscoelastic components, Titin (Connectin) filaments, collagens, physiological sarcomere length, and other factors that govern ventricular stiffness. Our review provides insights into the comparison of ventricular stiffness in different-sized ventricles between heterologous and homologous species, including non-model organisms.
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Grants
- JP22K15155 Japan Society for the Promotion of Science, Grant/Award Number
- JP20K21453 Japan Society for the Promotion of Science, Grant/Award Number
- JP20H04508 Japan Society for the Promotion of Science, Grant/Award Number
- JP21K19933 Japan Society for the Promotion of Science, Grant/Award Number
- JP20H04521 Japan Society for the Promotion of Science, Grant/Award Number
- JP17H02092 Japan Society for the Promotion of Science, Grant/Award Number
- JP23H00556 Japan Society for the Promotion of Science, Grant/Award Number
- JP17H06272 Japan Society for the Promotion of Science, Grant/Award Number
- JP17H00859 Japan Society for the Promotion of Science, Grant/Award Number
- JP25560214 Japan Society for the Promotion of Science, Grant/Award Number
- JP16K01385 Japan Society for the Promotion of Science, Grant/Award Number
- JP26282127 Japan Society for the Promotion of Science, Grant/Award Number
- The Futaba research grant program
- Research Grant from the Kawasaki Foundation in 2016 from Medical Science and Medical Welfare
- Medical Research Grant in 2010 from Takeda Science Foundation
- R03S005 Research Project Grant from Kawasaki Medical School
- R03B050 Research Project Grant from Kawasaki Medical School
- R01B054 Research Project Grant from Kawasaki Medical School
- H30B041 Research Project Grant from Kawasaki Medical School
- H30B016 Research Project Grant from Kawasaki Medical School
- H27B10 Research Project Grant from Kawasaki Medical School
- R02B039 Research Project Grant from Kawasaki Medical School
- H28B80 Research Project Grant from Kawasaki Medical School
- R05B016 Research Project Grant from Kawasaki Medical School
- Japan Society for the Promotion of Science, Grant/Award Number
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Affiliation(s)
- Yuu Usui
- First Department of PhysiologyKawasaki Medical SchoolKurashikiOkayamaJapan
| | - Akira Hanashima
- First Department of PhysiologyKawasaki Medical SchoolKurashikiOkayamaJapan
| | - Ken Hashimoto
- First Department of PhysiologyKawasaki Medical SchoolKurashikiOkayamaJapan
| | - Misaki Kimoto
- First Department of PhysiologyKawasaki Medical SchoolKurashikiOkayamaJapan
| | - Momoko Ohira
- First Department of PhysiologyKawasaki Medical SchoolKurashikiOkayamaJapan
| | - Satoshi Mohri
- First Department of PhysiologyKawasaki Medical SchoolKurashikiOkayamaJapan
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3
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Pawar SG, Saravanan PB, Gulati S, Pati S, Joshi M, Salam A, Khan N. Study the relationship between left atrial (LA) volume and left ventricular (LV) diastolic dysfunction and LV hypertrophy: Correlate LA volume with cardiovascular risk factors. Dis Mon 2024; 70:101675. [PMID: 38262769 DOI: 10.1016/j.disamonth.2024.101675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2024]
Abstract
Heart failure (HF) with normal ejection fraction - the isolated diastolic heart failure, depicts increasing prevalence and health care burden in recent times. Having less mortality rate compared to systolic heart failure but high morbidity, it is evolving as a major cardiac concern. With increasing clinical use of Left atrial volume (LAV) quantitation in clinical settings, LAV has emerged as an important independent predictor of cardiovascular outcome in HF with normal ejection fraction. This article is intended to review the diastolic and systolic heart failure, their association with left atrial volume, in depth study of Left atrial function dynamics with determinants of various functional and structural changes.
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Affiliation(s)
| | | | | | | | - Muskan Joshi
- Tbilisi State Medical University, Tbilisi, Georgia
| | - Ajal Salam
- Government Medical College, Kottayam, Kerala, India
| | - Nida Khan
- Jinnah Sindh Medical University, Karachi, Pakistan
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4
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Schauer A, Adams V, Augstein A, Jannasch A, Draskowski R, Kirchhoff V, Goto K, Mittag J, Galli R, Männel A, Barthel P, Linke A, Winzer EB. Sacubitril/Valsartan Improves Diastolic Function But Not Skeletal Muscle Function in a Rat Model of HFpEF. Int J Mol Sci 2021; 22:3570. [PMID: 33808232 PMCID: PMC8036273 DOI: 10.3390/ijms22073570] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 03/23/2021] [Accepted: 03/25/2021] [Indexed: 12/11/2022] Open
Abstract
The angiotensin receptor/neprilysin inhibitor Sacubitril/Valsartan (Sac/Val) has been shown to be beneficial in patients suffering from heart failure with reduced ejection fraction (HFrEF). However, the impact of Sac/Val in patients presenting with heart failure with preserved ejection fraction (HFpEF) is not yet clearly resolved. The present study aimed to reveal the influence of the drug on the functionality of the myocardium, the skeletal muscle, and the vasculature in a rat model of HFpEF. Female obese ZSF-1 rats received Sac/Val as a daily oral gavage for 12 weeks. Left ventricle (LV) function was assessed every four weeks using echocardiography. Prior to organ removal, invasive hemodynamic measurements were performed in both ventricles. Vascular function of the carotid artery and skeletal muscle function were monitored. Sac/Val treatment reduced E/é ratios, left ventricular end diastolic pressure (LVEDP) and myocardial stiffness as well as myocardial fibrosis and heart weight compared to the obese control group. Sac/Val slightly improved endothelial function in the carotid artery but had no impact on skeletal muscle function. Our results demonstrate striking effects of Sac/Val on the myocardial structure and function in a rat model of HFpEF. While vasodilation was slightly improved, functionality of the skeletal muscle remained unaffected.
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Affiliation(s)
- Antje Schauer
- Laboratory of Molecular and Experimental Cardiology, TU Dresden, Heart Center Dresden, 01307 Dresden, Germany; (V.A.); (A.A.); (R.D.); (V.K.); (K.G.); (A.M.); (P.B.); (A.L.); (E.B.W.)
| | - Volker Adams
- Laboratory of Molecular and Experimental Cardiology, TU Dresden, Heart Center Dresden, 01307 Dresden, Germany; (V.A.); (A.A.); (R.D.); (V.K.); (K.G.); (A.M.); (P.B.); (A.L.); (E.B.W.)
| | - Antje Augstein
- Laboratory of Molecular and Experimental Cardiology, TU Dresden, Heart Center Dresden, 01307 Dresden, Germany; (V.A.); (A.A.); (R.D.); (V.K.); (K.G.); (A.M.); (P.B.); (A.L.); (E.B.W.)
| | - Anett Jannasch
- Department of Cardiac Surgery, Carl Gustav Carus Faculty of Medicine, Technische Universität Dresden, Heart Centre Dresden, Fetscherstrasse 76, 01307 Dresden, Germany; (A.J.); (J.M.)
| | - Runa Draskowski
- Laboratory of Molecular and Experimental Cardiology, TU Dresden, Heart Center Dresden, 01307 Dresden, Germany; (V.A.); (A.A.); (R.D.); (V.K.); (K.G.); (A.M.); (P.B.); (A.L.); (E.B.W.)
| | - Virginia Kirchhoff
- Laboratory of Molecular and Experimental Cardiology, TU Dresden, Heart Center Dresden, 01307 Dresden, Germany; (V.A.); (A.A.); (R.D.); (V.K.); (K.G.); (A.M.); (P.B.); (A.L.); (E.B.W.)
| | - Keita Goto
- Laboratory of Molecular and Experimental Cardiology, TU Dresden, Heart Center Dresden, 01307 Dresden, Germany; (V.A.); (A.A.); (R.D.); (V.K.); (K.G.); (A.M.); (P.B.); (A.L.); (E.B.W.)
| | - Jeniffer Mittag
- Department of Cardiac Surgery, Carl Gustav Carus Faculty of Medicine, Technische Universität Dresden, Heart Centre Dresden, Fetscherstrasse 76, 01307 Dresden, Germany; (A.J.); (J.M.)
| | - Roberta Galli
- Clinical Sensoring and Monitoring, Department of Anesthesiology and Intensive Care Medicine, Faculty of Medicine, TU Dresden, 01307 Dresden, Germany;
| | - Anita Männel
- Laboratory of Molecular and Experimental Cardiology, TU Dresden, Heart Center Dresden, 01307 Dresden, Germany; (V.A.); (A.A.); (R.D.); (V.K.); (K.G.); (A.M.); (P.B.); (A.L.); (E.B.W.)
| | - Peggy Barthel
- Laboratory of Molecular and Experimental Cardiology, TU Dresden, Heart Center Dresden, 01307 Dresden, Germany; (V.A.); (A.A.); (R.D.); (V.K.); (K.G.); (A.M.); (P.B.); (A.L.); (E.B.W.)
| | - Axel Linke
- Laboratory of Molecular and Experimental Cardiology, TU Dresden, Heart Center Dresden, 01307 Dresden, Germany; (V.A.); (A.A.); (R.D.); (V.K.); (K.G.); (A.M.); (P.B.); (A.L.); (E.B.W.)
| | - Ephraim B. Winzer
- Laboratory of Molecular and Experimental Cardiology, TU Dresden, Heart Center Dresden, 01307 Dresden, Germany; (V.A.); (A.A.); (R.D.); (V.K.); (K.G.); (A.M.); (P.B.); (A.L.); (E.B.W.)
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5
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Torres WM, Barlow SC, Moore A, Freeburg LA, Hoenes A, Doviak H, Zile MR, Shazly T, Spinale FG. Changes in Myocardial Microstructure and Mechanics With Progressive Left Ventricular Pressure Overload. JACC Basic Transl Sci 2020; 5:463-480. [PMID: 32478208 PMCID: PMC7251228 DOI: 10.1016/j.jacbts.2020.02.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 02/27/2020] [Accepted: 02/28/2020] [Indexed: 01/08/2023]
Abstract
This study assessed the regional changes in myocardial geometry, microstructure, mechanical behavior, and properties that occur in response to progressive left ventricular pressure overload (LVPO) in a large animal model. Using an index of local biomechanical function at early onset of LVPO allowed for prediction of the magnitude of left ventricular chamber stiffness (Kc) and left atrial area at LVPO late timepoints. Our study found that LV myocardial collagen content alone was insufficient to identify mechanisms for LV myocardial stiffness with progression to heart failure with preserved ejection fraction (HFpEF). Serial assessment of regional biomechanical function might hold value in monitoring the natural history and progression of HFpEF, which would allow evaluation of novel therapeutic approaches.
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Key Words
- Ct, cycle time
- EDV, end-diastolic volume
- EF, ejection fraction
- ESV, end-systolic volume
- HF, heart failure
- HFpEF, heart failure with preserved ejection fraction
- HFrEF, heart failure with reduced ejection fraction
- IVRT, isovolumic relaxation time
- LA, left atrial
- LV, left ventricular
- LVPO, left ventricular pressure overload
- NT-proBNP, N-terminal pro-brain natriuretic peptide
- PCR, polymerase chain reaction
- PRSW, pre-load recruitable stroke work
- SHG, second harmonic generation
- STE, speckle tracking echocardiography
- echocardiography
- heart failure
- pressure overload
- qPCR, quantitative real-time PCR
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Affiliation(s)
- William M. Torres
- College of Engineering and Computing, University of South Carolina, Columbia, South Carolina
- Cardiovascular Translational Research Center, University of South Carolina School of Medicine and the Columbia Veteran Affairs Healthcare Center, Columbia, South Carolina
| | - Shayne C. Barlow
- Cardiovascular Translational Research Center, University of South Carolina School of Medicine and the Columbia Veteran Affairs Healthcare Center, Columbia, South Carolina
| | - Amber Moore
- Cardiovascular Translational Research Center, University of South Carolina School of Medicine and the Columbia Veteran Affairs Healthcare Center, Columbia, South Carolina
| | - Lisa A. Freeburg
- Cardiovascular Translational Research Center, University of South Carolina School of Medicine and the Columbia Veteran Affairs Healthcare Center, Columbia, South Carolina
| | - Abigail Hoenes
- Cardiovascular Translational Research Center, University of South Carolina School of Medicine and the Columbia Veteran Affairs Healthcare Center, Columbia, South Carolina
| | - Heather Doviak
- Cardiovascular Translational Research Center, University of South Carolina School of Medicine and the Columbia Veteran Affairs Healthcare Center, Columbia, South Carolina
| | - Michael R. Zile
- Medical University of South Carolina and RHJ Department of Veterans Affairs Medical Center, Charleston, South Carolina
| | - Tarek Shazly
- College of Engineering and Computing, University of South Carolina, Columbia, South Carolina
| | - Francis G. Spinale
- College of Engineering and Computing, University of South Carolina, Columbia, South Carolina
- Cardiovascular Translational Research Center, University of South Carolina School of Medicine and the Columbia Veteran Affairs Healthcare Center, Columbia, South Carolina
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6
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Pasipoularides A. Clinical-pathological correlations of BAV and the attendant thoracic aortopathies. Part 1: Pluridisciplinary perspective on their hemodynamics and morphomechanics. J Mol Cell Cardiol 2019; 133:223-232. [PMID: 31150733 DOI: 10.1016/j.yjmcc.2019.05.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 05/10/2019] [Accepted: 05/23/2019] [Indexed: 12/12/2022]
Abstract
Clinical BAV manifestations pertain to faulty aortic valve (AOV) function, the associated aortopathy, and other complications such as endocarditis, thrombosis and thromboembolism. BAV arises during valvulogenesis when 2 of the 3 leaflets/cusps of the AOV are fused together. Ensuing asymmetric BAV morphologies alter downstream ejection jet flow-trajectories. Based on BAV morphologies, ejection-flows exhibit different wall-impingement and scouring patterns in the proximal aorta, with excessive hydrodynamic wall-shear that correlates closely with mural vascular smooth muscle cell and extracellular matrix disruptions, revealing hemodynamic participation in the pathogenesis of BAV-associated aortopathies. Since the embryologic regions implicated in both BAV and aortopathies derive from neural crest cells and second heart field cells, there may exist a common multifactorial/polygenic embryological basis linking the abnormalities. The use of Electronic Health Records - encompassing integrated NGS variant panels and phenotypic data - in clinical studies could speed-up comprehensive understanding of multifactorial genetic-phenotypic and environmental factor interactions. This Survey represents the first in a 2-article pluridisciplinary work. Taken in toto, the series covers hemodynamic/morphomechanical and environmental (milieu intérieur) aspects in Part 1, and molecular, genetic and associated epigenetic aspects in Part 2. Together, Parts 1-2 should serve as a reference-milestone and driver for further pluridisciplinary research and its urgent translations in the clinical setting.
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Affiliation(s)
- Ares Pasipoularides
- Duke/NSF Center for Emerging Cardiovascular Technologies, Emeritus Faculty of Surgery and of Biomedical Engineering, Duke University School of Medicine and Graduate School, Durham, NC, USA.
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7
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Pasipoularides A. Morphomechanic phenotypic variability of sarcomeric cardiomyopathies: A multifactorial polygenic perspective. J Mol Cell Cardiol 2018; 126:23-35. [PMID: 30423317 DOI: 10.1016/j.yjmcc.2018.10.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 10/11/2018] [Accepted: 10/31/2018] [Indexed: 01/01/2023]
Abstract
Morphology underlies subdivision of the primary/heritable sarcomeric cardiomyopathies (CMs) into hypertrophic (HCM) and dilated (DCM). Next-generation DNA-sequencing (NGS) has identified important disease-variants, improving CM diagnosis, management, genetic screening, and prognosis. Although monogenic (Mendelian) analyses directly point at downstream studies, they disregard coexisting genomic variations and gene-by-gene interactions molding detailed CM-phenotypes. In-place of polygenic models, in accounting for observed defective genotype-phenotype correlations, fuzzy concepts having gradations of significance and unsharp domain-boundaries are invoked, including pleiotropy, genetic-heterogeneity, incomplete penetrance, and variable expressivity. HCM and DCM undoubtedly entail cooperativity of unidentified/elusive causative genomic-variants. Modern genomics can exploit comprehensive electronic/digital health records, facilitating consideration of multifactorial variant-models. Genome-wide association studies entailing high-fidelity solid-state catheterization, multimodal-imaging, molecular cardiology, systems biology and bioinformatics, will decipher accurate genotype-phenotype correlations and identify novel therapeutic-targets, fostering personalized medicine/cardiology. This review surveys successes and challenges of genetic/genomic approaches to CMs, and their impact on current and future clinical care.
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Affiliation(s)
- Ares Pasipoularides
- Duke/NSF Center for Emerging Cardiovascular Technologies, Emeritus Faculty of Surgery and of Biomedical Engineering, Duke University School of Medicine and Graduate School, Durham, NC, USA.
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8
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Pasipoularides A. Know Me! Unraveling the Riddle of Calcific Aortic Valve Disease by Bioinformatics. TOHOKU J EXP MED 2018; 243:255-261. [PMID: 29212966 DOI: 10.1620/tjem.243.255] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Ares Pasipoularides
- Emeritus Faculty of Surgery and of Biomedical Engineering, Duke University School of Medicine and Graduate School
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9
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Retos y controversias en miocardiopatía hipertrófica: visión integral desde la investigación básica, clínica y genética. Rev Esp Cardiol 2018. [DOI: 10.1016/j.recesp.2017.06.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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10
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Pasipoularides A. Implementing genome-driven personalized cardiology in clinical practice. J Mol Cell Cardiol 2018; 115:142-157. [PMID: 29343412 PMCID: PMC5820118 DOI: 10.1016/j.yjmcc.2018.01.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 01/04/2018] [Accepted: 01/12/2018] [Indexed: 12/18/2022]
Abstract
Genomics designates the coordinated investigation of a large number of genes in the context of a biological process or disease. It may be long before we attain comprehensive understanding of the genomics of common complex cardiovascular diseases (CVDs) such as inherited cardiomyopathies, valvular diseases, primary arrhythmogenic conditions, congenital heart syndromes, hypercholesterolemia and atherosclerotic heart disease, hypertensive syndromes, and heart failure with preserved/reduced ejection fraction. Nonetheless, as genomics is evolving rapidly, it is constructive to survey now pertinent concepts and breakthroughs. Today, clinical multimodal electronic medical/health records (EMRs/EHRs) incorporating genomic information establish a continuously-learning, vast knowledge-network with seamless cycling between clinical application and research. It can inform insights into specific pathogenetic pathways, guide biomarker-assisted precise diagnoses and individualized treatments, and stratify prognoses. Complex CVDs blend multiple interacting genomic variants, epigenetics, and environmental risk-factors, engendering progressions of multifaceted disease-manifestations, including clinical symptoms and signs. There is no straight-line linkage between genetic cause(s) or causal gene-variant(s) and disease phenotype(s). Because of interactions involving modifier-gene influences, (micro)-environmental, and epigenetic effects, the same variant may actually produce dissimilar abnormalities in different individuals. Implementing genome-driven personalized cardiology in clinical practice reveals that the study of CVDs at the level of molecules and cells can yield crucial clinical benefits. Complementing evidence-based medicine guidelines from large ("one-size fits all") randomized controlled trials, genomics-based personalized or precision cardiology is a most-creditable paradigm: It provides customizable approaches to prevent, diagnose, and manage CVDs with treatments directly/precisely aimed at causal defects identified by high-throughput genomic technologies. They encompass stem cell and gene therapies exploiting CRISPR-Cas9-gene-editing, and metabolomic-pharmacogenomic therapeutic modalities, precisely fine-tuned for the individual patient. Following the Human Genome Project, many expected genomics technology to provide imminent solutions to intractable medical problems, including CVDs. This eagerness has reaped some disappointment that advances have not yet materialized to the degree anticipated. Undoubtedly, personalized genetic/genomics testing is an emergent technology that should not be applied without supplementary phenotypic/clinical information: Genotype≠Phenotype. However, forthcoming advances in genomics will naturally build on prior attainments and, combined with insights into relevant epigenetics and environmental factors, can plausibly eradicate intractable CVDs, improving human health and well-being.
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Affiliation(s)
- Ares Pasipoularides
- Consulting Professor of Surgery, Emeritus Faculty of Surgery and of Biomedical Engineering, Duke University School of Medicine and Graduate School, Durham, NC 27710, USA.
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11
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Pasipoularides A. Challenges and Controversies in Hypertrophic Cardiomyopathy: Clinical, Genomic and Basic Science Perspectives. ACTA ACUST UNITED AC 2017; 71:132-138. [PMID: 28802532 DOI: 10.1016/j.rec.2017.07.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 07/05/2017] [Indexed: 11/29/2022]
Affiliation(s)
- Ares Pasipoularides
- Department of Surgery, School of Medicine, Duke University, Durham, North Carolina, United States.
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12
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Pasipoularides A. Genomic translational research: Paving the way to individualized cardiac functional analyses and personalized cardiology. Int J Cardiol 2016; 230:384-401. [PMID: 28057368 DOI: 10.1016/j.ijcard.2016.12.097] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 11/27/2016] [Accepted: 12/17/2016] [Indexed: 01/08/2023]
Abstract
For most of Medicine's past, the best that physicians could do to cope with disease prevention and treatment was based on the expected response of an average patient. Currently, however, a more personalized/precise approach to cardiology and medicine in general is becoming possible, as the cost of sequencing a human genome has declined substantially. As a result, we are witnessing an era of precipitous advances in biomedicine and bourgeoning understanding of the genetic basis of cardiovascular and other diseases, reminiscent of the resurgence of innovations in physico-mathematical sciences and biology-anatomy-cardiology in the Renaissance, a parallel time of radical change and reformation of medical knowledge, education and practice. Now on the horizon is an individualized, diverse patient-centered, approach to medical practice that encompasses the development of new, gene-based diagnostics and preventive medicine tactics, and offers the broadest range of personalized therapies based on pharmacogenetics. Over time, translation of genomic and high-tech approaches unquestionably will transform clinical practice in cardiology and medicine as a whole, with the adoption of new personalized medicine approaches and procedures. Clearly, future prospects far outweigh present accomplishments, which are best viewed as a promising start. It is now essential for pluridisciplinary health care providers to examine the drivers and barriers to the clinical adoption of this emerging revolutionary paradigm, in order to expedite the realization of its potential. So, we are not there yet, but we are definitely on our way.
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Affiliation(s)
- Ares Pasipoularides
- Department of Surgery, Duke University School of Medicine, Durham, NC, 27710, USA.
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13
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Mazumder R, Schroeder S, Mo X, Clymer BD, White RD, Kolipaka A. In vivo quantification of myocardial stiffness in hypertensive porcine hearts using MR elastography. J Magn Reson Imaging 2016; 45:813-820. [PMID: 27564862 DOI: 10.1002/jmri.25423] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 07/29/2016] [Indexed: 12/24/2022] Open
Abstract
PURPOSE To determine alteration in left ventricular (LV) myocardial stiffness (MS) with hypertension (HTN). Cardiac MR elastography (MRE) was used to estimate MS in HTN induced pigs and MRE-derived MS measurements were compared against LV pressure, thickness and circumferential strain. MATERIALS AND METHODS Renal-wrapping surgery was performed to induce HTN in eight pigs. LV catheterization (to measure pressure) and cardiac MRI (1.5 Tesla; gradient echo-MRE and tagging) was performed pre-surgery at baseline (Bx), and post-surgery at month 1 (M1) and month 2 (M2). Images were analyzed to estimate LV-MS, thickness, and circumferential strain across the cardiac cycle. The associations between end-diastolic (ED) and end-systolic (ES) MS and (i) mean LV pressure; (ii) ED and ES thickness, respectively; and (iii) circumferential strain were evaluated using Spearman's correlation method. RESULTS From Bx to M2, mean pressure, MRE-derived stiffness, and thickness increased while circumferential strain decreased significantly (slope test, P ≤ 0.05). Both ED and ES MS had significant positive correlation with (i) mean pressure (ED MS: ρ = 0.56; P = 0.005 and ES MS: ρ = 0.45; P = 0.03); (ii) ED thickness ( ρ = 0.73; P < 0.0001) and ES thickness ( ρ = 0.84; P < 0.0001), respectively; but demonstrated a negative trend with circumferential strain (ED MS: ρ = 0.31 and ES MS: ρ = 0.37). CONCLUSION This study demonstrated that, in a HTN porcine model, MRE-derived MS increased with increase in pressure and thickness. LEVEL OF EVIDENCE 1 J. Magn. Reson. Imaging 2017;45:813-820.
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Affiliation(s)
- Ria Mazumder
- Department of Electrical and Computer Engineering, 205 Dreese Laboratories, The Ohio State University, Columbus, Ohio, USA.,Department of Radiology, Room 460, The Ohio State University, Columbus, Ohio, USA.,Department of Biomedical Engineering, 265 Kirkbride Hall, Walnut Street, Widener University, Chester, PA
| | - Samuel Schroeder
- Department of Radiology, Room 460, The Ohio State University, Columbus, Ohio, USA.,Department of Mechanical Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Xiaokui Mo
- Center for Biostatistics, Department of Biomedical Informatics, Room 320D, Lincoln Tower, Columbus, Ohio, USA
| | - Bradley D Clymer
- Department of Electrical and Computer Engineering, 205 Dreese Laboratories, The Ohio State University, Columbus, Ohio, USA
| | - Richard D White
- Department of Radiology, Room 460, The Ohio State University, Columbus, Ohio, USA.,Department of Internal Medicine-Division of Cardiovascular Medicine, 244 Davis Heart & Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Arunark Kolipaka
- Department of Radiology, Room 460, The Ohio State University, Columbus, Ohio, USA.,Department of Internal Medicine-Division of Cardiovascular Medicine, 244 Davis Heart & Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
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14
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Pasipoularides A. Calcific Aortic Valve Disease: Part 2-Morphomechanical Abnormalities, Gene Reexpression, and Gender Effects on Ventricular Hypertrophy and Its Reversibility. J Cardiovasc Transl Res 2016; 9:374-99. [PMID: 27184804 PMCID: PMC4992466 DOI: 10.1007/s12265-016-9695-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 05/03/2016] [Indexed: 02/07/2023]
Abstract
In part 1, we considered cytomolecular mechanisms underlying calcific aortic valve disease (CAVD), hemodynamics, and adaptive feedbacks controlling pathological left ventricular hypertrophy provoked by ensuing aortic valvular stenosis (AVS). In part 2, we survey diverse signal transduction pathways that precede cellular/molecular mechanisms controlling hypertrophic gene expression by activation of specific transcription factors that induce sarcomere replication in-parallel. Such signaling pathways represent potential targets for therapeutic intervention and prevention of decompensation/failure. Hypertrophy provoking signals, in the form of dynamic stresses and ligand/effector molecules that bind to specific receptors to initiate the hypertrophy, are transcribed across the sarcolemma by several second messengers. They comprise intricate feedback mechanisms involving gene network cascades, specific signaling molecules encompassing G protein-coupled receptors and mechanotransducers, and myocardial stresses. Future multidisciplinary studies will characterize the adaptive/maladaptive nature of the AVS-induced hypertrophy, its gender- and individual patient-dependent peculiarities, and its response to surgical/medical interventions. They will herald more effective, precision medicine treatments.
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Affiliation(s)
- Ares Pasipoularides
- Duke University School of Medicine, Durham, NC, USA.
- Duke/NSF Research Center for Emerging Cardiovascular Technologies, Duke University, Durham, NC, 27710, USA.
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15
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Calcific Aortic Valve Disease: Part 1--Molecular Pathogenetic Aspects, Hemodynamics, and Adaptive Feedbacks. J Cardiovasc Transl Res 2016; 9:102-18. [PMID: 26891845 DOI: 10.1007/s12265-016-9679-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 01/27/2016] [Indexed: 01/01/2023]
Abstract
Aortic valvular stenosis (AVS), produced by calcific aortic valve disease (CAVD) causing reduced cusp opening, afflicts mostly older persons eventually requiring valve replacement. CAVD had been considered "degenerative," but newer investigations implicate active mechanisms similar to atherogenesis--genetic predisposition and signaling pathways, lipoprotein deposits, chronic inflammation, and calcification/osteogenesis. Consequently, CAVD may eventually be controlled/reversed by lifestyle and pharmacogenomics remedies. Its management should be comprehensive, embracing not only the valve but also the left ventricle and the arterial system with their interdependent morphomechanics/hemodynamics, which underlie the ensuing diastolic and systolic LV dysfunction. Compared to even a couple of decades ago, we now have an increased appreciation of genomic and cytomolecular pathogenetic mechanisms underlying CAVD. Future pluridisciplinary studies will characterize better and more completely its pathobiology, evolution, and overall dynamics, encompassing intricate feedback processes involving specific signaling molecules and gene network cascades. They will herald more effective, personalized medicine treatments of CAVD/AVS.
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16
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Liu Y, Royston TJ, Klatt D, Lewandowski ED. Cardiac MR elastography of the mouse: Initial results. Magn Reson Med 2016; 76:1879-1886. [PMID: 26749052 DOI: 10.1002/mrm.26030] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 10/09/2015] [Accepted: 10/10/2015] [Indexed: 12/22/2022]
Abstract
PURPOSE Many cardiovascular diseases are associated with abnormal function of myocardial contractility or dilatability, which is related to elasticity changes of the myocardium over the cardiac cycle. The mouse is a common animal model in studies of the progression of various cardiomyopathies. We introduce a novel noninvasive approach using microscopic scale MR elastography (MRE) to measure the myocardium stiffness change during the cardiac cycle on a mouse model. METHODS A harmonic mechanical wave of 400 Hz was introduced into the mouse body. An electrocardiograph-gated and respiratory-gated fractional encoding cine-MRE pulse sequence was applied to encode the resulting oscillatory motion on a short-axis slice of the heart. Five healthy mice (age range, 3-13.5 mo) were examined. The weighted summation effective stiffness of the left ventricle wall during the cardiac cycle was estimated. RESULTS The ratio of stiffness at end diastole and end systole was 0.5-0.67. Additionally, variation in shear wave amplitude in the left ventricle wall throughout the cardiac cycle was measured and found to correlate with estimates of stiffness variation. CONCLUSION This study demonstrates the feasibility of implementing cardiac MRE on a mouse model. Magn Reson Med 76:1879-1886, 2016. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Yifei Liu
- Department of Mechanical & Industrial Engineering, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Thomas J Royston
- Department of Mechanical & Industrial Engineering, University of Illinois at Chicago, Chicago, Illinois, USA.,Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Dieter Klatt
- Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois, USA
| | - E Douglas Lewandowski
- Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois, USA.,Center for Cardiovascular Research, University of Illinois at Chicago, Chicago, Illinois, USA.,Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois, USA
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17
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Linking Genes to Cardiovascular Diseases: Gene Action and Gene-Environment Interactions. J Cardiovasc Transl Res 2015; 8:506-27. [PMID: 26545598 DOI: 10.1007/s12265-015-9658-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 10/08/2015] [Indexed: 01/22/2023]
Abstract
A unique myocardial characteristic is its ability to grow/remodel in order to adapt; this is determined partly by genes and partly by the environment and the milieu intérieur. In the "post-genomic" era, a need is emerging to elucidate the physiologic functions of myocardial genes, as well as potential adaptive and maladaptive modulations induced by environmental/epigenetic factors. Genome sequencing and analysis advances have become exponential lately, with escalation of our knowledge concerning sometimes controversial genetic underpinnings of cardiovascular diseases. Current technologies can identify candidate genes variously involved in diverse normal/abnormal morphomechanical phenotypes, and offer insights into multiple genetic factors implicated in complex cardiovascular syndromes. The expression profiles of thousands of genes are regularly ascertained under diverse conditions. Global analyses of gene expression levels are useful for cataloging genes and correlated phenotypes, and for elucidating the role of genes in maladies. Comparative expression of gene networks coupled to complex disorders can contribute insights as to how "modifier genes" influence the expressed phenotypes. Increasingly, a more comprehensive and detailed systematic understanding of genetic abnormalities underlying, for example, various genetic cardiomyopathies is emerging. Implementing genomic findings in cardiology practice may well lead directly to better diagnosing and therapeutics. There is currently evolving a strong appreciation for the value of studying gene anomalies, and doing so in a non-disjointed, cohesive manner. However, it is challenging for many-practitioners and investigators-to comprehend, interpret, and utilize the clinically increasingly accessible and affordable cardiovascular genomics studies. This survey addresses the need for fundamental understanding in this vital area.
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18
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Pasipoularides A. Mechanotransduction Mechanisms for Intraventricular Diastolic Vortex Forces and Myocardial Deformations: Part 2. J Cardiovasc Transl Res 2015; 8:293-318. [PMID: 25971844 PMCID: PMC4519381 DOI: 10.1007/s12265-015-9630-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 04/27/2015] [Indexed: 01/10/2023]
Abstract
Epigenetic mechanisms are fundamental in cardiac adaptations, remodeling, reverse remodeling, and disease. A primary goal of translational cardiovascular research is recognizing whether disease-related changes in phenotype can be averted by eliminating or reducing the effects of environmental epigenetic risks. There may be significant medical benefits in using gene-by-environment interaction knowledge to prevent or reverse organ abnormalities and disease. This survey proposes that "environmental" forces associated with diastolic RV/LV rotatory flows exert important, albeit still unappreciated, epigenetic actions influencing functional and morphological cardiac adaptations. Mechanisms analogous to Murray's law of hydrodynamic shear-induced endothelial cell modulation of vascular geometry are likely to link diastolic vortex-associated shear, torque and "squeeze" forces to RV/LV adaptations. The time has come to explore a new paradigm in which such forces play a fundamental epigenetic role, and to work out how heart cells react to them. Findings from various imaging modalities, computational fluid dynamics, molecular cell biology and cytomechanics are considered. The following are examined, among others: structural dynamics of myocardial cells (endocardium, cardiomyocytes, and fibroblasts), cytoskeleton, nucleoskeleton, and extracellular matrix; mechanotransduction and signaling; and mechanical epigenetic influences on genetic expression. To help integrate and focus relevant pluridisciplinary research, rotatory RV/LV filling flow is placed within a working context that has a cytomechanics perspective. This new frontier in cardiac research should uncover versatile mechanistic insights linking filling vortex patterns and attendant forces to variable expressions of gene regulation in RV/LV myocardium. In due course, it should reveal intrinsic homeostatic arrangements that support ventricular myocardial function and adaptability.
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Affiliation(s)
- Ares Pasipoularides
- Department of Surgery, Duke University School of Medicine, Durham, NC, 27710, USA,
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19
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Wassenaar PA, Eleswarpu CN, Schroeder SA, Mo X, Raterman BD, White RD, Kolipaka A. Measuring age-dependent myocardial stiffness across the cardiac cycle using MR elastography: A reproducibility study. Magn Reson Med 2015; 75:1586-93. [PMID: 26010456 DOI: 10.1002/mrm.25760] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 04/08/2015] [Accepted: 04/11/2015] [Indexed: 12/23/2022]
Abstract
PURPOSE To assess reproducibility in measuring left ventricular (LV) myocardial stiffness in volunteers throughout the cardiac cycle using MR elastography (MRE) and to determine its correlation with age. METHODS Cardiac MRE (CMRE) was performed on 29 normal volunteers, with ages ranging from 21 to 73 years. For assessing reproducibility of CMRE-derived stiffness measurements, scans were repeated per volunteer. Wave images were acquired throughout the LV myocardium, and were analyzed to obtain mean stiffness during the cardiac cycle. CMRE-derived stiffness values were correlated to age. RESULTS Concordance correlation coefficient revealed good interscan agreement with rc of 0.77, with P-value < 0.0001. Significantly higher myocardial stiffness was observed during end-systole (ES) compared with end-diastole (ED) across all subjects. Additionally, increased deviation between ES and ED stiffness was observed with increased age. CONCLUSION CMRE-derived stiffness is reproducible, with myocardial stiffness changing cyclically across the cardiac cycle. Stiffness is significantly higher during ES compared with ED. With age, ES myocardial stiffness increases more than ED, giving rise to an increased deviation between the two.
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Affiliation(s)
- Peter A Wassenaar
- Department of Radiology, The Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Chethanya N Eleswarpu
- Department of Radiology, The Ohio State University College of Medicine, Columbus, Ohio, USA.,Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Samuel A Schroeder
- Department of Radiology, The Ohio State University College of Medicine, Columbus, Ohio, USA.,Department of Mechanical Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Xiaokui Mo
- Center for Biostatistics, The Ohio State University, Columbus, Ohio, USA
| | - Brian D Raterman
- Department of Radiology, The Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Richard D White
- Department of Radiology, The Ohio State University College of Medicine, Columbus, Ohio, USA.,Department of Internal Medicine-Division of Cardiovascular Medicine, The Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Arunark Kolipaka
- Department of Radiology, The Ohio State University College of Medicine, Columbus, Ohio, USA.,Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio, USA.,Department of Internal Medicine-Division of Cardiovascular Medicine, The Ohio State University College of Medicine, Columbus, Ohio, USA
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20
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Ellims AH, Taylor AJ. T 1 Mapping Techniques in Assessment of Ventricular Stiffness. CURRENT CARDIOVASCULAR IMAGING REPORTS 2015. [DOI: 10.1007/s12410-014-9318-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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21
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Mossahebi S, Zhu S, Kovács SJ. Fractionating E-Wave Deceleration Time Into Its Stiffness and Relaxation Components Distinguishes Pseudonormal From Normal Filling. Circ Cardiovasc Imaging 2015; 8:CIRCIMAGING.114.002177. [DOI: 10.1161/circimaging.114.002177] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background—
Pseudonormal Doppler E-wave filling patterns indicate diastolic dysfunction but are indistinguishable from the normal filling pattern. For accurate classification, maneuvers to alter load or to additionally measure peak
E
′ are required. E-wave deceleration time (DT) has been fractionated into its stiffness (DT
s
) and relaxation (DT
r
) components (DT=DT
s
+DT
r
) by analyzing E-waves via the parametrized diastolic filling formalism. The method has been validated with DT
s
and DT
r
correlating with simultaneous catheterization-derived stiffness (dP/dV) and relaxation (
τ
) with
r
=0.82 and
r
=0.94, respectively. We hypothesize that DT fractionation can (1) distinguish between unblinded (
E
′ known) normal versus pseudonormal age-matched groups with normal left ventricular ejection fraction, and (2) distinguish between blinded (
E
′ unknown) normal versus pseudonormal groups, based solely on E-wave analysis.
Methods and Results—
Data (763 E-waves) from 15 age-matched, pseudonormal (elevated
E
/
E
′) and 15 normal subjects were analyzed. Conventional echocardiographic and parametrized diastolic filling stiffness (
k
) and relaxation (
c
) parameters and DT
s
and DT
r
were compared. Conventional diastolic function parameters did not differentiate between unblinded groups, whereas
k
,
c
(
P
<0.001) and DT
s
, DT
r
(
P
<0.001) did. Independent, blinded (
E
′ not provided) analysis of 42 subjects (30 subjects from unblinded training set and 12 additional subjects from validation set, 581 E-waves) showed that
R
(=DT
r
/DT) had high sensitivity (0.90) and specificity (0.86) in differentiating pseudonormal from normal once
E
′ revealed actual classification.
Conclusions—
arametrized diastolic filling–based E-wave analysis (
k
,
c
or DT
s
and DT
r
) can differentiate normal versus pseudonormal filling patterns without requiring knowledge of
E
′.
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Affiliation(s)
- Sina Mossahebi
- From the Cardiovascular Biophysics Laboratory, Cardiovascular Division (S.M., S.Z., S.J.K), Department of Physics (S.M., S.Z., S.J.K.), and Department of Medicine, Cardiovascular Division (S.J.K), Washington University School of Medicine, St. Louis, MO
| | - Simeng Zhu
- From the Cardiovascular Biophysics Laboratory, Cardiovascular Division (S.M., S.Z., S.J.K), Department of Physics (S.M., S.Z., S.J.K.), and Department of Medicine, Cardiovascular Division (S.J.K), Washington University School of Medicine, St. Louis, MO
| | - Sándor J. Kovács
- From the Cardiovascular Biophysics Laboratory, Cardiovascular Division (S.M., S.Z., S.J.K), Department of Physics (S.M., S.Z., S.J.K.), and Department of Medicine, Cardiovascular Division (S.J.K), Washington University School of Medicine, St. Louis, MO
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22
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Morimont P, Pironet A, Desaive T, Chase G, Lambermont B. Early detection of abnormal left ventricular relaxation in acute myocardial ischemia with a quadratic model. Med Eng Phys 2014; 36:1101-5. [DOI: 10.1016/j.medengphy.2014.06.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 05/14/2014] [Accepted: 06/04/2014] [Indexed: 11/16/2022]
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23
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Basar EZ, Corapcioglu F, Babaoglu K, Anik Y, Gorur Daglioz G, Dedeoglu R. Are cardiac magnetic resonance imaging and radionuclide ventriculography good options against echocardiography for evaluation of anthracycline induced chronic cardiotoxicity in childhood cancer survivors? Pediatr Hematol Oncol 2014; 31:237-52. [PMID: 24499452 DOI: 10.3109/08880018.2013.851753] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Anthracyclines are widely used for the treatment of solid tumors in pediatric oncology. However, their uses may be limited by progressive chronic cardiotoxicity related to the cumulative dosage. The aims of this study are to compare diagnostic techniques and prepare an algorithm for diagnosis of anthracycline induced chronic cardiotoxicity. The patients were evaluated according to age, sex, time elapsed since the last dose of anthracycline treatment, presence of cardiovascular symptoms, follow-up duration, type of anthracycline, cumulative anthracycline dose, and concomitant mediastinal radiation therapy. Late subclinical cardiotoxicity was detected by history, physical examination, electrocardiography (ECG), Holter monitor, echocardiography (ECHO), radionuclide ventriculography (MUGA), and cardiac magnetic resonance imaging (MRI). Thirty-seven male and 19 female patients with a median age of 11.2 ± 4.6 (range, 3.5-22.0) years were included in the study. Patients were grouped according to cumulative anthracycline doses. Subclinical cardiac dysfunction was detected in 20 patients by at least one of ECHO, MRI or MUGA after anthracycline chemotherapy. We revealed that other than ECHO, MRI and MUGA have high clinical importance for evaluating subclinical late cardiac complications in children treated with anthracyclines.
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Affiliation(s)
- Evic Zeynep Basar
- Department of Pediatric Oncology, Kocaeli University, Kocaeli, Turkey
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24
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Hillestad V, Kramer F, Golz S, Knorr A, Andersson KB, Christensen G. Long-term levosimendan treatment improves systolic function and myocardial relaxation in mice with cardiomyocyte-specific disruption of the Serca2 gene. J Appl Physiol (1985) 2013; 115:1572-80. [PMID: 24072410 DOI: 10.1152/japplphysiol.01044.2012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In human heart failure (HF), reduced cardiac function has, at least partly, been ascribed to altered calcium homeostasis in cardiomyocytes. The effects of the calcium sensitizer levosimendan on diastolic dysfunction caused by reduced removal of calcium from cytosol in early diastole are not well known. In this study, we investigated the effect of long-term levosimendan treatment in a murine model of HF where the sarco(endo)plasmatic reticulum ATPase (Serca) gene is specifically disrupted in the cardiomyocytes, leading to reduced removal of cytosolic calcium. After induction of Serca2 gene disruption, these mice develop marked diastolic dysfunction as well as impaired contractility. SERCA2 knockout (SERCA2KO) mice were treated with levosimendan or vehicle from the time of KO induction. At the 7-wk end point, cardiac function was assessed by echocardiography and pressure measurements. Vehicle-treated SERCA2KO mice showed significantly diminished left-ventricular (LV) contractility, as shown by decreased ejection fraction, stroke volume, and cardiac output. LV pressure measurements revealed a marked increase in the time constant (τ) of isovolumetric pressure decay, showing impaired relaxation. Levosimendan treatment significantly improved all three systolic parameters. Moreover, a significant reduction in τ toward normalization indicated improved relaxation. Gene-expression analysis, however, revealed an increase in genes related to production of the ECM in animals treated with levosimendan. In conclusion, long-term levosimendan treatment improves both contractility and relaxation in a heart-failure model with marked diastolic dysfunction due to reduced calcium transients. However, altered gene expression related to fibrosis was observed.
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Affiliation(s)
- Vigdis Hillestad
- Institute for Experimental Medical Research, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway
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25
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Pasipoularides A. Evaluation of right and left ventricular diastolic filling. J Cardiovasc Transl Res 2013; 6:623-39. [PMID: 23585308 PMCID: PMC3713169 DOI: 10.1007/s12265-013-9461-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 03/27/2013] [Indexed: 01/08/2023]
Abstract
A conceptual fluid-dynamics framework for diastolic filling is developed. The convective deceleration load (CDL) is identified as an important determinant of ventricular inflow during the E wave (A wave) upstroke. Convective deceleration occurs as blood moves from the inflow anulus through larger-area cross-sections toward the expanding walls. Chamber dilatation underlies previously unrecognized alterations in intraventricular flow dynamics. The larger the chamber, the larger becomes the endocardial surface and the CDL. CDL magnitude affects strongly the attainable E wave (A wave) peak. This underlies the concept of diastolic ventriculoannular disproportion. Large vortices, whose strength decreases with chamber dilatation, ensue after the E wave peak and impound inflow kinetic energy, averting an inflow-impeding, convective Bernoulli pressure rise. This reduces the CDL by a variable extent depending on vortical intensity. Accordingly, the filling vortex facilitates filling to varying degrees, depending on chamber volume. The new framework provides stimulus for functional genomics research, aimed at new insights into ventricular remodeling.
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MESH Headings
- Animals
- Biomechanical Phenomena
- Diastole
- Disease Progression
- Genetic Predisposition to Disease
- Genomics
- Heart Failure/genetics
- Heart Failure/physiopathology
- Humans
- Hypertrophy, Left Ventricular/genetics
- Hypertrophy, Left Ventricular/physiopathology
- Hypertrophy, Right Ventricular/genetics
- Hypertrophy, Right Ventricular/physiopathology
- Models, Cardiovascular
- Phenotype
- Stroke Volume
- Ventricular Dysfunction, Left/genetics
- Ventricular Dysfunction, Left/physiopathology
- Ventricular Dysfunction, Right/genetics
- Ventricular Dysfunction, Right/physiopathology
- Ventricular Function, Left/genetics
- Ventricular Function, Right/genetics
- Ventricular Pressure
- Ventricular Remodeling
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Affiliation(s)
- Ares Pasipoularides
- Department of Surgery, Duke University School of Medicine, HAFS-7th floor, DUMC 3704, Durham, NC 27710, USA.
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26
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Pasipoularides A. Flujo diastólico ventricular derecho e izquierdo: ¿por qué son bajos los gradientes de presión intraventricular medidos? Rev Esp Cardiol 2013. [DOI: 10.1016/j.recesp.2012.07.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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27
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Pasipoularides A. Right and left ventricular diastolic pressure-volume relations: a comprehensive review. J Cardiovasc Transl Res 2012. [PMID: 23179133 DOI: 10.1007/s12265-012-9424-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Ventricular compliance alterations can affect cardiac performance and adaptations. Moreover, diastolic mechanics are important in assessing both diastolic and systolic function, since any filling impairment can compromise systolic function. A sigmoidal passive filling pressure-volume relationship, developed using chronically instrumented, awake-animal disease models, is clinically adaptable to evaluating diastolic dynamics using subject-specific micromanometric and volumetric data from the entire filling period of any heartbeat(s). This innovative relationship is the global, integrated expression of chamber geometry, wall thickness, and passive myocardial wall properties. Chamber and myocardial compliance curves of both ventricles can be computed by the sigmoidal methodology over the entire filling period and plotted over appropriate filling pressure ranges. Important characteristics of the compliance curves can be examined and compared between the right and the left ventricle and for different physiological and pathological conditions. The sigmoidal paradigm is more accurate and, therefore, a better alternative to the conventional exponential pressure-volume approximation.
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Affiliation(s)
- Ares Pasipoularides
- Department of Surgery, Duke University School of Medicine, HAFS, 7th floor, DUMC 3704, Durham, NC 27710, USA.
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28
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Pasipoularides A. Right and left ventricular diastolic flow field: why are measured intraventricular pressure gradients small? ACTA ACUST UNITED AC 2012; 66:337-41. [PMID: 24775813 DOI: 10.1016/j.rec.2012.07.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 07/30/2012] [Indexed: 11/19/2022]
Affiliation(s)
- Ares Pasipoularides
- Department of Surgery, Duke University School of Medicine, Durham, NC, United States.
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Kolipaka A, Aggarwal SR, McGee KP, Anavekar N, Manduca A, Ehman RL, Araoz PA. Magnetic resonance elastography as a method to estimate myocardial contractility. J Magn Reson Imaging 2012; 36:120-7. [PMID: 22334349 PMCID: PMC3355216 DOI: 10.1002/jmri.23616] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Accepted: 01/13/2012] [Indexed: 12/14/2022] Open
Abstract
PURPOSE To determine whether increasing epinephrine infusion in an in vivo pig model is associated with an increase in end-systolic magnetic resonance elastography (MRE)-derived effective stiffness. MATERIALS AND METHODS Finite element modeling (FEM) was performed to determine the range of myocardial wall thicknesses that could be used for analysis. Then MRE was performed on five pigs to measure the end-systolic effective stiffness with epinephrine infusion. Epinephrine was continuously infused intravenously in each pig to increase the heart rate in increments of 20%. For each such increase end-systolic effective stiffness was measured using MRE. In each pig, Student's t-test was used to compare effective end-systolic stiffness at baseline and at initial infusion of epinephrine. Least-square linear regression was performed to determine the correlation between normalized end-systolic effective stiffness and increase in heart rate with epinephrine infusion. RESULTS FEM showed that phase gradient inversion could be performed on wall thickness ≈≥1.5 cm. In pigs, effective end-systolic stiffness significantly increased from baseline to the first infusion in all pigs (P = 0.047). A linear correlation was found between normalized effective end-systolic stiffness and percent increase in heart rate by epinephrine infusion with R(2) ranging from 0.86-0.99 in four pigs. In one of the pigs the R(2) value was 0.1. A linear correlation with R(2) = 0.58 was found between normalized effective end-systolic stiffness and percent increase in heart rate when pooling data points from all pigs. CONCLUSION Noninvasive MRE-derived end-systolic effective myocardial stiffness may be a surrogate for myocardial contractility.
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Affiliation(s)
| | | | | | - Nandan Anavekar
- Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States
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ZHONG LIANG, GHISTA DHANJOON, NG EDDIEYK, CHUA TERRANCESJ, LEE CHUENN, LIM SOOTEIK, TAN RUSAN, CHUA LEOKPOH. LEFT VENTRICULAR FUNCTIONAL INDICES BASED ON LEFT VENTRICULAR ELASTANCES AND SHAPE FACTOR. J MECH MED BIOL 2011. [DOI: 10.1142/s0219519407002182] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This study characterizes left ventricular function in terms of passive and active elastances (Ep & Ea) and shape factor index. Both the active elastance and shape factor indices can be employed as contractility indices. The work also demonstrates how Ep and Ea can explain LV pressure dynamics in terms of LV volume dynamics.
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Affiliation(s)
- LIANG ZHONG
- Department of Cardiology, National Heart Center, SingHealth, Mistri Wing 17, 3rd Hospital Avenue, Singapore
| | - DHANJOO N. GHISTA
- Division of Engineering, Science and Technology, University of New South Wales Asia, Singapore
| | - EDDIE Y.-K. NG
- College of Engineering, School of Mechanical & Aerospace Engineering, Nanyang Technological University, Singapore
| | - TERRANCE S.-J. CHUA
- Department of Cardiology, National Heart Center, SingHealth, Mistri Wing 17, 3rd Hospital Avenue, Singapore
| | - CHUEN N. LEE
- Department of Cardiac, Thoracic and Vascular Surgery, National University Hospital, Singapore
| | - SOO TEIK LIM
- Department of Cardiology, National Heart Center, SingHealth, Mistri Wing 17, 3rd Hospital Avenue, Singapore
| | - RU SAN TAN
- Department of Cardiology, National Heart Center, SingHealth, Mistri Wing 17, 3rd Hospital Avenue, Singapore
| | - LEOK POH CHUA
- College of Engineering, School of Mechanical & Aerospace Engineering, Nanyang Technological University, Singapore
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Pasipoularides A. LV twisting and untwisting in HCM: ejection begets filling. Diastolic functional aspects of HCM. Am Heart J 2011; 162:798-810. [PMID: 22093194 DOI: 10.1016/j.ahj.2011.08.019] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Accepted: 08/21/2011] [Indexed: 12/31/2022]
Abstract
Conventional and emerging concepts on mechanisms by which hypertrophic cardiomyopathy (HCM) engenders diastolic dysfunction are surveyed. A shift from familiar left ventricular (LV) diastolic function approaches to large-scale (twist-untwist) and small-scale (titin unfolding-refolding, etc.) wall rebound models, incorporating interaction and dynamic distortions and rearrangements of myofiber sheets and ultrastructural constituents, is suggested. Such an emerging new paradigm of diastolic dynamics, emphasizing the relationship of myofiber sheet and ultraconstituent distortion to LV mechanics and end-systolic shape, might clarify intricate patterns of early diastolic rebound and suction, needed for LV filling in many of the polymorphic phenotypes of HCM.
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Matyal R, Skubas NJ, Shernan SK, Mahmood F. Perioperative assessment of diastolic dysfunction. Anesth Analg 2011; 113:449-72. [PMID: 21813627 DOI: 10.1213/ane.0b013e31822649ac] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Assessment of diastolic function should be a component of a comprehensive perioperative transesophageal echocardiographic examination. Abnormal diastolic function exists in >50% of patients presenting for cardiac and high-risk noncardiac surgery, and has been shown to be an independent predictor of adverse postoperative outcome. Normalcy of systolic function in 50% of patients with congestive heart failure implicates diastolic dysfunction as the probable etiology. Comprehensive evaluation of diastolic function requires the use of various, load-dependent Doppler techniques This is further complicated by the additional effects of dehydration and anesthetic drugs on myocardial relaxation and compliance as assessed by these Doppler measures. The availability of more sophisticated Doppler techniques, e.g., Doppler tissue imaging and flow propagation velocity, makes it possible to interrogate left ventricular diastolic function with greater precision, analyze specific stages of diastole, and to differentiate abnormalities of relaxation from compliance. Additionally, various Doppler-derived ratios can be used to estimate left ventricular filling pressures. The varying hemodynamic environment of the operating room mandates modification of the diagnostic algorithms used for ambulatory cardiac patients when left ventricular diastolic function is evaluated with transesophageal echocardiography in anesthetized surgical patients.
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Affiliation(s)
- Robina Matyal
- Department of Anesthesia and Critical Care Medicine, Beth Israel Deaconess Medical Center, CC-454, 1 Deaconess Rd., Boston, MA 02215, USA.
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Zhong L, Ghista DN, Tan RS. Left ventricular wall stress compendium. Comput Methods Biomech Biomed Engin 2011; 15:1015-41. [PMID: 21547783 DOI: 10.1080/10255842.2011.569885] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Left ventricular (LV) wall stress has intrigued scientists and cardiologists since the time of Lame and Laplace in 1800s. The left ventricle is an intriguing organ structure, whose intrinsic design enables it to fill and contract. The development of wall stress is intriguing to cardiologists and biomedical engineers. The role of left ventricle wall stress in cardiac perfusion and pumping as well as in cardiac pathophysiology is a relatively unexplored phenomenon. But even for us to assess this role, we first need accurate determination of in vivo wall stress. However, at this point, 150 years after Lame estimated left ventricle wall stress using the elasticity theory, we are still in the exploratory stage of (i) developing left ventricle models that properly represent left ventricle anatomy and physiology and (ii) obtaining data on left ventricle dynamics. In this paper, we are responding to the need for a comprehensive survey of left ventricle wall stress models, their mechanics, stress computation and results. We have provided herein a compendium of major type of wall stress models: thin-wall models based on the Laplace law, thick-wall shell models, elasticity theory model, thick-wall large deformation models and finite element models. We have compared the mean stress values of these models as well as the variation of stress across the wall. All of the thin-wall and thick-wall shell models are based on idealised ellipsoidal and spherical geometries. However, the elasticity model's shape can vary through the cycle, to simulate the more ellipsoidal shape of the left ventricle in the systolic phase. The finite element models have more representative geometries, but are generally based on animal data, which limits their medical relevance. This paper can enable readers to obtain a comprehensive perspective of left ventricle wall stress models, of how to employ them to determine wall stresses, and be cognizant of the assumptions involved in the use of specific models.
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Affiliation(s)
- L Zhong
- Department of Cardiology, National Heart Centre Singapore, Mistri Wing 17 Third Hospital Avenue, Singapore 168752, Singapore.
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Kolipaka A, Araoz PA, McGee KP, Manduca A, Ehman RL. Magnetic resonance elastography as a method for the assessment of effective myocardial stiffness throughout the cardiac cycle. Magn Reson Med 2010; 64:862-70. [PMID: 20578052 PMCID: PMC3035166 DOI: 10.1002/mrm.22467] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Accepted: 03/10/2010] [Indexed: 12/28/2022]
Abstract
MR elastography (MRE) is a noninvasive technique in which images of externally generated waves propagating in tissue are used to measure stiffness. The first aim is to determine, from a range of driver configurations, the optimal driver for the purpose of generating waves within the heart in vivo. The second aim is to quantify the shear stiffness of normal myocardium throughout the cardiac cycle using MRE and to compare MRE stiffness to left ventricular chamber pressure in an in vivo pig model. MRE was performed in six pigs with six different driver setups, including no motion, three noninvasive drivers, and two invasive drivers. MRE wave displacement amplitudes were calculated for each driver. During the same MRI examination, left ventricular pressure and MRI-measured left ventricular volume were obtained, and MRE myocardial stiffness was calculated for 20 phases of the cardiac cycle. No discernible waves were imaged when no external motion was applied, and a single pneumatic drum driver produced higher amplitude waves than the other noninvasive drivers (P < 0.05). Pressure-volume loops overlaid onto stiffness-volume loops showed good visual agreement. Pressure and MRE-measured effective stiffness showed good correlation (R(2) = 0.84). MRE shows potential as a noninvasive method for estimating effective myocardial stiffness throughout the cardiac cycle.
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Fukuda N, Fukuda Y, Morishita S, Sakabe K, Shinohara H, Tamura Y. Diastolic flow velocity pattern of the left anterior descending coronary artery in hypertrophied heart, with special reference to the difference between hypertrophic cardiomyopathy and hypertensive left ventricular hypertrophy. J Echocardiogr 2010; 8:45-51. [PMID: 27278660 DOI: 10.1007/s12574-009-0031-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Revised: 11/12/2009] [Accepted: 11/23/2009] [Indexed: 11/27/2022]
Abstract
BACKGROUND This study aimed to clarify the characteristics of diastolic flow velocity pattern of the left anterior descending coronary artery (LAD) in patients with left ventricular hypertrophy (LVH), and the difference in diastolic LAD flow velocity pattern between hypertensive LVH and hypertrophic cardiomyopathy (HCM). METHODS The flow velocity pattern was recorded at the mid-portion of the LAD by high-frequency transthoracic Doppler echocardiography in 22 patients with HCM, 10 hypertensive patients with LVH [LVH(+)HT], and 9 hypertensive patients without LVH [LVH(-)HT]. The diastolic flow pattern was analyzed. Standard two-dimensional echocardiogram and apexcardiogram (ACG) were also recorded. RESULTS The interventricular septal thickness (IVST) and the sum of the IVST and LV posterior wall thickness (PWT) (IVST + PWT) were greater in HCM than in HT (p < 0.01) patients. Early diastolic upstroke time (D-UT) of the LAD flow velocity wave was longest in HCM, and was longer in LVH(+)HT than in LVH(-)HT (p < 0.01) patients. Direct correlation was found between D-UT and IVST, IVST + PWT in patients with LVH(+)HT and LVH(-)HT (r = 0.80, 0.79, respectively; p < 0.01), but no correlation was found between these parameters in HCM. Late-diastolic step (LDS) formation of the LAD flow velocity wave was observed in 68% of HCM, 20% of LVH(+)HT, but none of the LVH(-)HT patients. The A wave ratio of ACG was higher in patients with LDS than in those without (p < 0.01). The LDS occurred coincidently with the A wave of ACG. CONCLUSIONS The diastolic LAD flow velocity pattern in hypertrophied heart is characterized by slow acceleration and LDS formation, reflecting impaired relaxation and increased stiffness of the LV, respectively. These abnormalities correlate with the degree of hypertrophy in hypertensive heart, but do not correlate with that in HCM.
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Affiliation(s)
- Nobuo Fukuda
- Department of Cardiology and Clinical Research, National Hospital Organization Zentsuji Hospital, 2-1-1 Senyu-cho, Zentsuji, Kagawa, 765-8507, Japan.
| | - Yamato Fukuda
- Department of Cardiology and Clinical Research, National Hospital Organization Zentsuji Hospital, 2-1-1 Senyu-cho, Zentsuji, Kagawa, 765-8507, Japan
| | - Satofumi Morishita
- Department of Cardiology and Clinical Research, National Hospital Organization Zentsuji Hospital, 2-1-1 Senyu-cho, Zentsuji, Kagawa, 765-8507, Japan
| | - Koichi Sakabe
- Department of Cardiology and Clinical Research, National Hospital Organization Zentsuji Hospital, 2-1-1 Senyu-cho, Zentsuji, Kagawa, 765-8507, Japan
| | - Hisanori Shinohara
- Department of Cardiology and Clinical Research, National Hospital Organization Zentsuji Hospital, 2-1-1 Senyu-cho, Zentsuji, Kagawa, 765-8507, Japan
| | - Yoshiyuki Tamura
- Department of Cardiology and Clinical Research, National Hospital Organization Zentsuji Hospital, 2-1-1 Senyu-cho, Zentsuji, Kagawa, 765-8507, Japan
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Diastolic function in healthy humans: non-invasive assessment and the impact of acute and chronic exercise. Eur J Appl Physiol 2009; 108:1-14. [DOI: 10.1007/s00421-009-1233-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/25/2009] [Indexed: 01/27/2023]
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Kolipaka A, McGee KP, Araoz PA, Glaser KJ, Manduca A, Ehman RL. Evaluation of a rapid, multiphase MRE sequence in a heart-simulating phantom. Magn Reson Med 2009; 62:691-8. [PMID: 19572388 PMCID: PMC3076071 DOI: 10.1002/mrm.22048] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2008] [Accepted: 03/26/2009] [Indexed: 01/22/2023]
Abstract
The aims of this study were to validate stiffness estimates of a phantom undergoing cyclic deformation obtained using a multiphase magnetic resonance elastography (MRE) imaging sequence by comparison with those obtained using a single-phase MRE sequence and to quantify the stability of the multiphase-derived stiffness estimates as a function of deformation frequency and imaging parameters. A spherical rubber shell of 10 cm diameter and 1 cm thickness was connected to a computerized flow pump to produce cyclic pressure variations within the phantom. The phantom was imaged at cyclic pressures between 18-72 bpm using single-phase and multiphase MRE acquisitions. The shear stiffness of the phantom was resolved using a spherical shell wave inversion algorithm. Shear stiffness was averaged over the slice of interest and plotted against pressure within the phantom. A linear correlation was observed between stiffness and pressure. Good correlation (R(2) = 0.98) was observed between the stiffness estimates obtained using the standard single-phase and the multiphase pulse sequences. Stiffness estimates obtained using multiphase MRE were stable when the fraction of the deformation period required for acquisition of a single image was not greater than 42%. The results demonstrate the potential of multiphase MRE technique for imaging dynamic organs, such as the heart.
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Romero R, Espinoza J, Gonçalves LF, Gomez R, Medina L, Silva M, Chaiworapongsa T, Yoon BH, Ghezzi F, Lee W, Treadwell M, Berry SM, Maymon E, Mazor M, DeVore G. Fetal cardiac dysfunction in preterm premature rupture of membranes. J Matern Fetal Neonatal Med 2009. [DOI: 10.1080/jmf.16.3.146.157] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- R Romero
- Perinatology Research Branch NICHD/NIH/DHHS Detroit Michigan and Bethesda, Maryland USA
| | - J Espinoza
- Perinatology Research Branch NICHD/NIH/DHHS Detroit Michigan and Bethesda, Maryland USA
| | - LF Gonçalves
- Perinatology Research Branch NICHD/NIH/DHHS Detroit Michigan and Bethesda, Maryland USA
| | - R Gomez
- CEDIP, Department of Obstetrics and Gynecology, Sotero del Rio Hospital Puente Alto Chile
| | - L Medina
- CEDIP, Department of Obstetrics and Gynecology, Sotero del Rio Hospital Puente Alto Chile
| | - M Silva
- Department of Pediatric Cardiology Joana de Gusmao Children's Hospital Florianopolis Brazil
| | - T Chaiworapongsa
- Perinatology Research Branch NICHD/NIH/DHHS Detroit Michigan and Bethesda, Maryland USA
| | - BH Yoon
- Department of Obstetrics and Gynecology Seoul National University Seoul Korea
| | - F Ghezzi
- Department of Obstetrics and Gynecology University of Insubria Varese Italy
| | - W Lee
- Department of Obstetrics and Gynecology William Beaumont Hospital Royal Oak Michigan USA
| | - M Treadwell
- Department of Obstetrics and Gynecology Wayne State University/Hutzel Hospital Detroit Michigan USA
| | - SM Berry
- Department of Obstetrics and Gynecology Emory University Hospital Atlanta Georgia USA
| | - E Maymon
- Department of Obstetrics and Gynecology Ben Gurion University of the Negev Beer Sheva Israel
| | - M Mazor
- Department of Obstetrics and Gynecology Ben Gurion University of the Negev Beer Sheva Israel
| | - G DeVore
- Feral Diagnostic Centre Pasadena California USA
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Kolipaka A, McGee KP, Araoz PA, Glaser KJ, Manduca A, Romano AJ, Ehman RL. MR elastography as a method for the assessment of myocardial stiffness: comparison with an established pressure-volume model in a left ventricular model of the heart. Magn Reson Med 2009; 62:135-40. [PMID: 19353657 PMCID: PMC3003430 DOI: 10.1002/mrm.21991] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Accepted: 01/19/2009] [Indexed: 12/16/2022]
Abstract
Magnetic resonance elastography (MRE) measurements of shear stiffness (mu) in a spherical phantom experiencing both static and cyclic pressure variations were compared to those derived from an established pressure-volume (P-V)-based model. A spherical phantom was constructed using a silicone rubber composite of 10 cm inner diameter and 1.3 cm thickness. A gradient echo MRE sequence was used to determine mu within the phantom at static and cyclic pressures ranging from 55 to 90 mmHg. Average values of mu using MRE were obtained within a region of interest and were compared to the P-V-derived estimates. Under both static and cyclic pressure conditions, the P-V- and MRE-based estimates of mu ranged from 98.2 to 155.1 kPa and 96.2 to 150.8 kPa, respectively. Correlation coefficients (R(2)) of 0.98 and 0.97 between the P-V and MRE-based estimates of shear stiffness measurements were obtained. For both static and cyclic pressures, MRE-based measures of mu agree with those derived from a P-V model, suggesting that MRE can be used as a new, noninvasive method of assessing mu in sphere-like fluid-filled organs such as the heart.
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Affiliation(s)
| | | | | | | | | | - Anthony J. Romano
- Acoustics Division, Naval Research Laboratory, Washington DC, United States
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Meierhenrich R, Schütz W, Gauss A. [Left ventricular diastolic dysfunction. Implications for anesthesia and critical care]. Anaesthesist 2009; 57:1053-68. [PMID: 18958434 DOI: 10.1007/s00101-008-1457-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Over the last two decades there has been a growing recognition that cardiac function is not solely determined by systolic but also essentially by diastolic function. Left ventricular diastolic dysfunction is characterized by an impairment of ventricular filling caused either by abnormal relaxation, an active energy consuming process or decreased compliance, which is determined by passive tissue properties of the ventricle. Doppler echocardiography, including tissue Doppler imaging, has emerged as the preferred clinical tool for the assessment of left ventricular diastolic function. Recently the importance of left ventricular diastolic function is increasingly being recognized also during the perioperative period. Newer studies have shown that after cardiopulmonary bypass there is a significant decrease in left ventricular compliance. Experimental studies have demonstrated that sepsis is associated with a decrease in both active relaxation and ventricular compliance. Initial studies are also focusing on therapeutic options for patients with isolated diastolic dysfunction.
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Affiliation(s)
- R Meierhenrich
- Klinik für Anästhesiologie, Universitätsklinikum Ulm, Steinhövelstr. 9, 89075 Ulm, Deutschland.
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Elgeti T, Rump J, Hamhaber U, Papazoglou S, Hamm B, Braun J, Sack I. Cardiac magnetic resonance elastography. Initial results. Invest Radiol 2008; 43:762-72. [PMID: 18923255 DOI: 10.1097/rli.0b013e3181822085] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
OBJECTIVES To develop cardiac magnetic resonance elastography (MRE) for noninvasively measuring left ventricular (LV) pressure-volume (P-V) work. MATERIAL AND METHODS The anterior chest wall of 8 healthy volunteers was vibrated by 24.3-Hz acoustic waves for stimulating oscillating shear deformation in myocardium and adjacent blood. The induced motion was recorded by an electrocardiogram-gated, vibration-synchronized and segmented gradient-recalled echo MRE sequence acquiring 360 phase-contrast wave images with a temporal resolution of 5.16 milliseconds in the short-axis view during controlled breathing. Relative changes in wave amplitudes served as a measure of LV pressure variation during the cardiac cycle. MRE pressure data were combined with LV volumes obtained from segmentation of 3D cine-steady-state free precession data sets. RESULTS Shear wave amplitudes decreased from diastole to systole, which reflects the dynamics of myocardial shear modulus variations during the cardiac cycle. Assuming spherical shear stress, a linear relationship between myocardial stiffness and LV pressure was derived. The MRE-measured pressure was plotted as a function of LV volumes. Characteristic P-V cycles displayed an isovolumetric increase in pressure during early systole, whereas less pronounced volume conservation was observed in early diastole. Mean cardiac P-V work in all volunteers was 0.85 +/- 0.11 J. CONCLUSION In vivo cardiac MRE is a noninvasive method for measuring pressure-related heart function determined by shear modulus variations in the LV wall. This is the first noninvasive mechanical test of cardiac work in the human heart and is potentially useful for assessing pathologies associated with increased myocardial stiffness such as diastolic dysfunction.
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Affiliation(s)
- Thomas Elgeti
- Department of Radiology, Charité-Universitätsmedizin Berlin, Campus Mitte, Berlin, Germany
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Targeted myocardial microinjections of a biocomposite material reduces infarct expansion in pigs. Ann Thorac Surg 2008; 86:1268-76. [PMID: 18805174 DOI: 10.1016/j.athoracsur.2008.04.107] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2008] [Revised: 04/28/2008] [Accepted: 04/29/2008] [Indexed: 11/21/2022]
Abstract
BACKGROUND Left ventricular (LV) remodeling after myocardial infarction (MI) commonly causes infarct expansion (IE). This study sought to interrupt IE through microinjections of a biocompatible composite material into the post-MI myocardium. METHODS MI was created in 21 pigs (coronary ligation). Radiopaque markers (2-mm diameter) were placed for IE (fluoroscopy). Pigs were randomized for microinjections (25 injections; 2- x 2-cm array; 200 microL/injection) at 7 days post-MI of a fibrin-alginate composite (Fib-Alg; fibrinogen, fibronectin, factor XIII, gelatin-grafted alginate, thrombin; n = 11) or saline (n = 10). RESULTS At 7 days after injection (14 days post-MI), LV posterior wall thickness was higher in the Fib-Alg group than in the saline group (1.07 +/- 0.11 vs 0.69 +/- 0.07 cm, respectively, p = 0.002). At 28 days post-MI, the area within the markers (IE) increased from baseline (1 cm2) in the saline (1.71 +/- 0.13 cm2, p = 0.010) and Fib-Alg groups (1.44 +/- 0.23 cm2, p < 0.001). However, the change in IE at 21 and 28 days post-MI was reduced in the Fib-Alg group (p=0.043 and p=0.019). Total collagen content within the MI region was similar in the saline and Fib-Alg groups (12.8 +/- 1.7 and 11.6 +/- 1.5 microg/mg, respectively, p = NS). However, extractable collagen, indicative of solubility, was lower in the Fib-Alg group than the saline group (59.1 +/- 3.5 vs 71.0 +/- 6.1 microg/mL, p = 0.020). CONCLUSIONS Targeted myocardial microinjection of the biocomposite attenuated the post-MI decrease in LV wall thickness and infarct expansion. Thus, intraoperative microinjections of biocompatible material may provide a novel approach for interrupting post-MI LV remodeling.
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44
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Aortic regurgitation: disease progression and management. ACTA ACUST UNITED AC 2008; 5:269-79. [DOI: 10.1038/ncpcardio1179] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Accepted: 01/18/2008] [Indexed: 11/08/2022]
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Riordan MM, Kovács SJ. Elucidation of spatially distinct compensatory mechanisms in diastole: radial compensation for impaired longitudinal filling in left ventricular hypertrophy. J Appl Physiol (1985) 2007; 104:513-20. [PMID: 18032579 DOI: 10.1152/japplphysiol.00848.2007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Cardiac output maintenance is so fundamental that, when regional systolic function is impaired, as during ischemia, nonischemic segments compensate by becoming hypercontractile. By analogy, diastolic compensatory mechanisms that maintain filling volume must exist but remain to be fully elucidated. Viewing filling in spatially distinct (longitudinal, radial) mechanistic terms facilitates elucidation of diastolic compensatory mechanisms. Because impairment of longitudinal (long axis) diastolic function (DF) in left ventricular hypertrophy (LVH) is established, we hypothesized that to maintain filling volume, radial (short-axis) filling function would compensate. In 20 normal left ventricular ejection fraction (LVEF) subjects (10 with LVH, 10 without LVH), we analyzed longitudinal function via Doppler tissue imaging of mitral annular motion and radial function as change in short-axis endocardial dimension via M-mode. The spatial (long axis, short axis) endocardial LV dimensions and their changes allowed assignment of E-wave filling volume into (cylindrical geometry-based) longitudinal and radial components. Despite indistinguishable (P = 0.70) E-wave velocity-time integrals (E-wave filling volume surrogate), systolic stroke volumes, and end-diastolic volumes in the LVH and control groups, longitudinal volume in absolute terms and the percent of E-wave volume accommodated longitudinally were reduced in the LVH group (P < 0.05 and P < 0.01, respectively), whereas the percent of E-wave volume accommodated radially was enhanced (P < 0.01). We conclude that, in normal LVEF (decreased longitudinal volume accommodation) LVH subjects vs. controls, spatially distinct compensatory mechanisms in diastole manifest as increased radial volume accommodation per unit of E-wave filling volume. Assessment of spatially distinct diastolic compensatory mechanisms in other pathophysiological subsets is warranted.
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Affiliation(s)
- Matt M Riordan
- Department of Biomedical Engineering, School of Engineering and Applied Science, Washington University School of Medicine, St. Louis, MO 63110, USA
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Abstract
Cardiovascular morbidity and mortality resulting from congestive heart failure are major concerns for the critical care physician. Although heart failure is commonly associated with impaired systolic function, in up to one half of cases, heart failure occurs exclusively on the basis of an impairment of diastolic function. Diastole is the summation of processes by which the heart loses its ability to generate force and shorten and returns to its precontractile state. The two principal processes responsible for diastole are relaxation and passive pressure-volume properties of the ventricle. Echocardiography provides a comprehensive, noninvasive evaluation of diastolic filling of the ventricle, myocardial relaxation, and ventricular stiffness; the information obtained by echocardiography has prognostic value and is a guide to proper therapy. This article reviews the physiology of diastole, the pathogenesis of diastolic heart failure, and the diagnosis of diastolic dysfunction, with a focus on the diagnostic utility of echocardiography and an emphasis on those areas of greatest interest to the critical care physician.
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Affiliation(s)
- Brian D Hoit
- Department of Medicine, University Hospitals of Cleveland and Case Western Reserve University, Cleveland, OH, USA.
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47
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Klotz S, Danser AHJ, Foronjy RF, Oz MC, Wang J, Mancini D, D'Armiento J, Burkhoff D. The impact of angiotensin-converting enzyme inhibitor therapy on the extracellular collagen matrix during left ventricular assist device support in patients with end-stage heart failure. J Am Coll Cardiol 2007; 49:1166-74. [PMID: 17367660 DOI: 10.1016/j.jacc.2006.10.071] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2006] [Revised: 10/04/2006] [Accepted: 10/09/2006] [Indexed: 10/23/2022]
Abstract
OBJECTIVES We hypothesized that angiotensin-converting enzyme inhibition (ACE-I) during left ventricular assist device (LVAD) support in patients with end-stage heart failure prevents potentially deleterious effects on the extracellular matrix. BACKGROUND Left ventricular assist device-induced mechanical unloading increases myocardial collagen and stiffness and may contribute to the low rate of recovery. METHODS Heart samples obtained before and after LVAD implantation were divided into groups depending on whether the patients received (n = 7) or did not receive (control; n = 15) ACE-I. At transplant, ex vivo pressure-volume relationships were measured and chamber and myocardial stiffness constants determined. Myocardial tissue content of angiotensin (Ang) I and II, matrix metalloproteinase (MMP)-1, tissue inhibitor of MMPs (TIMP)-1, and total and cross-linked collagen was measured. RESULTS Duration of support was comparable between ACE-I and control subjects (96 +/- 65 days vs. 109 +/- 22 days). Pre-LVAD Ang I and II and total and cross-linked collagen were similar between groups. Post-LVAD, Ang II was reduced in the ACE-I group but increased in control subjects (181 +/- 7 fmol/g vs. 262 +/- 41 fmol/g; p < 0.05). Similarly, cross-linked collagen decreased during LVAD support in the ACE-I group. Left ventricular (LV) mass and myocardial stiffness were lower in the ACE-I group. ACE-I normalized the LV and right ventricular (RV) MMP-1/TIMP-1 ratio. Collagen content and characteristics of the RV were not affected by ACE-I. CONCLUSIONS ACE-I therapy was associated with decreased Ang II, myocardial collagen content, and myocardial stiffness during LVAD support. This is the first demonstration of a pharmacologic therapy that can impact myocardial properties during mechanical unloading, and it could foster new lines of investigation in strategies of enhancing myocardial recovery during LVAD support.
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Affiliation(s)
- Stefan Klotz
- Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, New York, USA
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48
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Ciampi Q, Betocchi S, Losi MA, Lombardi R, Villari B, Chiariello M. Effect of hypertrophy on left ventricular diastolic function in patients with hypertrophic cardiomyopathy. Heart Int 2006; 2:106. [PMID: 21977259 PMCID: PMC3184662 DOI: 10.4081/hi.2006.106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Background. Hypertrophic cardiomyopathy (HCM) is characterized by asymmetric LV hypertrophy (LVH) and impairment in diastolic function. We assess the relationship between LVH and invasive indexes of diastolic function. Methods. 21 HCM patients underwent cardiac catheterization to assess pulmonary capillary wedge pressure, LV end-diastolic pressure (measured by microtip catheters), and LV volumes (calculated by simultaneous radionuclide angiography). We calculated from LV pressure the time constant of isovolumetric relaxation (τ, variable asymptote method, ms), and from LV pressure and volume the constant of chamber stiffness (k, ml−1). LVH was assessed by different indexes: maximal wall thickness, number of hypertrophied LV segments, LVH index, and Wigle’s score. Results. Wigle’s score was directly related to pulmonary capillary Wedge pressure (r=0.436, p=0.048), peak V wave of pulmonary capillary wedge pressure (r=0.503, p=0.024), LV end-diastolic pressure (r=0.643, p=0.002) and k (r=0.564, p=0.015). HCM patients were divided into 2 groups according to Wigle’s score: 10 with mild or moderate LVH (< 8), and 11 with severe LVH (≥ 8). HCM patients with severe LVH showed a higher pulmonary capillary Wedge pressure (15.1±7.2 vs 9.5±2.4, p=0.033), peak V wave of pulmonary capillary wedge pressure (20.7±4.6 vs 14.6±4.9, p=0.011), LV end-diastolic pressure (23.9±10.9 vs 10.6±2.5, p=0.002), k (0.0465±0.032 vs 0.015±0.007, p=0.022) and LV outflow tract gradient (72±36 mmHg vs 29±30 mmHg, p=0.01).τ was similar in the two groups. Other indexes of LVH were not related to diastolic function. Conclusions. Wigle’s score is the only index of LVH that relates to invasive indices of diastolic function.
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Affiliation(s)
- Quirino Ciampi
- Department of Clinical Medicine, Cardiovascular & Immunological Sciences, "Federico II" University School of Medicine, Naples - Italy
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49
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Gill RM, Jones BD, Corbly AK, Wang J, Braz JC, Sandusky GE, Wang J, Shen W. Cardiac diastolic dysfunction in conscious dogs with heart failure induced by chronic coronary microembolization. Am J Physiol Heart Circ Physiol 2006; 291:H3154-8. [PMID: 16877566 DOI: 10.1152/ajpheart.00052.2006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Left ventricular (LV) diastolic dysfunction is a fundamental impairment in congestive heart failure (CHF). This study examined LV diastolic function in the canine model of CHF induced by chronic coronary embolization (CCE). Dogs were implanted with coronary catheters (both left anterior descending and circumflex arteries) for CCE and instrumented for measurement of LV pressure and dimension. Heart failure was elicited by daily intracoronary injections of microspheres (1.2 million, 90- to 120-microm diameter) for 24 +/- 4 days, resulting in significant depression of cardiac systolic function. After CCE, LV maximum negative change of pressure with time (dP/dt(min)) decreased by 25 +/- 2% (P < 0.05) and LV isovolumic relaxation constant and duration increased by 19 +/- 5% and 25 +/- 6%, respectively (both P < 0.05), indicating an impairment of LV active relaxation, which was cardiac preload independent. LV passive viscoelastic properties were evaluated from the LV end-diastolic pressure (EDP)-volume (EDV) relationship (EDP = be(alpha*EDV)) during brief inferior vena caval occlusion and acute volume loading, while the chamber stiffness coefficient (alpha) increased by 62 +/- 10% (P < 0.05) and the stiffness constant (k) increased by 66 +/- 13% after CCE. The regional myocardial diastolic stiffness in LV anterior and posterior walls was increased by 70 +/- 25% and 63 +/- 24% (both P < 0.05), respectively, after CCE, associated with marked fibrosis, increase in collagen I and III, and enhancement of plasminogen activator inhibitor-1 (PAI-1) protein expression. Thus along with depressed LV systolic function there is significant impairment of LV diastolic relaxation and increase in chamber stiffness, with development of myocardial fibrosis and activation of PAI-1, in the canine model of CHF induced by CCE.
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Affiliation(s)
- Robert M Gill
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN 46285, USA
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50
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Zhong L, Ghista DN, Ng EYK, Lim ST, Tan RS, Chua LP. Explaining Left Ventricular Pressure Dynamics in Terms of LV Passive and Active Elastances. Proc Inst Mech Eng H 2006; 220:647-55. [PMID: 16898221 DOI: 10.1243/09544119jeim123] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
There has been much characterization of the heart as a pump by means of models based on elastance and compliance. The present paper puts forward the new concept of time-varying passive and active elastance. The biomechanical basis of cyclic elastances of the left ventricle (LV) is presented. Elastance is defined in terms of the relationship between ventricular pressure and volume as d P = Ed V + Vd E, where E includes passive elastance, Ep, and active elastance, Ea. By incorporating this concept in LV models to simulate diastolic (filling) and systolic phases, a time-varying expression has been obtained for Ea, and an LV volume dependent expression has been obtained for Ep. It is proposed to use these two elastances Ea and Ep to represent the intrinsic LV properties. The active elastance, Ea, can be used to characterize the LV contractile state and represents LV pressure variation due to LV volume variation (such as during the filling and ejection phases). The passive elastance, Ep, can serve as a measure of LV resistance to filling. Furthermore, it has been demonstrated how the LV pressure dynamics (and LV pressure response to LV volume) can be explained in terms of Ea and Ep.
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Affiliation(s)
- Liang Zhong
- College of Engineering, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore
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