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MacIver DH, Scrase T, Zhang H. Left ventricular contractance: A new measure of contractile function. Int J Cardiol 2023; 371:345-353. [PMID: 36084798 DOI: 10.1016/j.ijcard.2022.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 09/02/2022] [Indexed: 12/14/2022]
Abstract
AIMS Myocardial contractility is poorly defined and difficult to compare between studies. Contractance or myocardial active strain energy density (MASED) measures the mechanical work done per unit volume (with units of kJ/m3) by any cardiac tissue during contraction. Contractance is an ideal candidate for measuring contractile function as it combines information from both stress and strain. METHODS AND RESULTS Data obtained from three previously published experimental studies using trabecular tissue was used to provide contemporaneous nominal stress and strain data in 18 different scenarios with different loading conditions. Contractance varied in the differing loading conditions with values of 1.16 (low preload), 2.02 (high afterload) and 3.76 kJ/m3 (normal). Contractance varied between 0 with isometric loading and 2.14 kJ/m3 with an isotonic and moderate afterload. Increasing inotropy increased contractance to 4.7 kJ/m3. CONCLUSION We showed that calculating MASED was feasible and provided a measure of energy production (work done) per unit volume of myocardium during contraction. The new term for contractile function, contractance, can be defined and quantified by MASED. Contractance measures contractile function in differing preload, afterload and inotropic settings. The method of measuring contractance is transferable to the assessment of global and regional systolic function.
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Affiliation(s)
- David H MacIver
- Department of Cardiology, Taunton & Somerset Hospital, United Kingdom; Biological Physics Group, Department of Astronomy and Physics, University of Manchester, Manchester, United Kingdom.
| | - Thomas Scrase
- Biological Physics Group, Department of Astronomy and Physics, University of Manchester, Manchester, United Kingdom
| | - Henggui Zhang
- Biological Physics Group, Department of Astronomy and Physics, University of Manchester, Manchester, United Kingdom
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2
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MacIver DH, Partridge JB, Agger P, Stephenson RS, Boukens BJD, Omann C, Jarvis JC, Zhang H. The end of the unique myocardial band: Part II. Clinical and functional considerations. Eur J Cardiothorac Surg 2018; 53:120-128. [PMID: 29029119 DOI: 10.1093/ejcts/ezx335] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Accepted: 08/20/2017] [Indexed: 12/25/2022] Open
Abstract
Two of the leading concepts of mural ventricular architecture are the unique myocardial band and the myocardial mesh model. We have described, in an accompanying article published in this journal, how the anatomical, histological and high-resolution computed tomographic studies strongly favour the latter concept. We now extend the argument to describe the linkage between mural architecture and ventricular function in both health and disease. We show that clinical imaging by echocardiography and magnetic resonance imaging, and electrophysiological studies, all support the myocardial mesh model. We also provide evidence that the unique myocardial band model is not compatible with much of scientific research.
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Affiliation(s)
- David H MacIver
- Department of Cardiology, Taunton and Somerset Hospital, Musgrove Park, Taunton, UK.,Medical Education, University of Bristol, Senate House, Bristol, UK.,Biological Physics Group, School of Physics and Astronomy, University of Manchester, Manchester, UK
| | - John B Partridge
- Eurobodalla Unit, Rural Clinical School of the ANU College of Medicine, Biology & Environment, Batemans Bay, NSW, Australia
| | - Peter Agger
- Department of Paediatrics, Aarhus University Hospital, Aarhus, Denmark.,Comparative Medicine Lab, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Robert S Stephenson
- Comparative Medicine Lab, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Bastiaan J D Boukens
- Department of Medical Biology, Academic Medical Centre, Amsterdam University, Amsterdam, Netherlands
| | - Camilla Omann
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark
| | - Jonathan C Jarvis
- School of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Henggui Zhang
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Manchester, UK
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Lopez-Candales A, Hernandez-Suarez DF, Menendez FL. Are Measures of Left Ventricular Longitudinal Shortening Affected by Left Atrial Enlargement? Cardiol Res 2018; 9:1-6. [PMID: 29479378 PMCID: PMC5819621 DOI: 10.14740/cr637w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 11/30/2017] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Even though left atrial (LA) size and function are intimately related to left ventricular (LV) diastolic dysfunction, the role of LA with regard to LV systolic function is less clear. Consequently, we examined the potential association that might exist between measures of longitudinal LV systolic shortening and LA dilation using LA volume index (LAVI). METHODS In this retrospective analysis, data from 75 echocardiograms (mean age 53 ± 14; range 24 - 89 years; mean body surface area (BSA) 2.0 ± 0.3) were analyzed. RESULTS Peak global longitudinal (PGLS) correlated best with LV mass index (LVMI) followed by mitral annular systolic excursion (MAPSE), and age. Similar results were obtained when analyzing the best variables that correlated with LAVI. Finally, MAPSE correlated best with PGLS, then with MA tissue Doppler systolic velocity, BSA, and LAVI in that order. All patients had normal LV ejection fraction (LVEF) and normal sinus rhythm when studied. CONCLUSIONS LAVI does not directly affect LV systolic function and longitudinal measures of LV shortening are mainly dependent on LV mass. Additional studies are now required to determine how these associations vary when different degrees of LV dilatation and systolic dysfunction are included in the analysis.
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Affiliation(s)
- Angel Lopez-Candales
- Cardiovascular Medicine Division, School of Medicine, University of Puerto Rico, San Juan, Puerto Rico
| | | | - Francisco Lopez Menendez
- Division of Cardiovascular Health and Disease, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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Lopez-Candales A, Hernandez-Suarez DF, Lopez Menendez F. Mitral Annular Dynamics and Left Ventricular Diastole. Cardiol Res 2017; 8:228-231. [PMID: 29118885 PMCID: PMC5667710 DOI: 10.14740/cr602w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 09/25/2017] [Indexed: 11/17/2022] Open
Abstract
Background Though diastolic interrogation of the mitral annulus (MA) using tissue Doppler imaging (TDI) has been quite useful in assessing left ventricular (LV) diastolic function, the relative contribution of the previous cycle MA systolic displacement or velocity components to subsequent LV diastole has not been previously investigated. We therefore sought to determine the association between MA systolic dynamics and LV diastolic function parameters. Methods For this retrospective study, only complete echocardiograms having good endocardial border resolution of both left atrial (LA) and LV chambers with M-mode (MAPSE) and tissue Doppler of the lateral MA (MA TDI S’) as well as complete Doppler data to perform assessment of LV diastole were included in our analysis. Results Data from 100 patients (mean age 54 ± 14) showed that both MA systolic displacement and velocity correlate with LV ejection fraction (P < 0.05). Only MA displacement was associated with age and LV mass. Most importantly no correlation was found between MAPSE and LV diastole. However, in sharp contrast MA TDI S’ correlated with MA relaxation velocities during both early and late LV diastole. Conclusion Even though MAPSE and MA TDI S’ are surrogate measures of LV ejection fraction, only MA TDI S’ correlates with diastolic MA velocities as no correlation was identified between MAPSE and measures of LV diastole. Additional studies are now warranted to explore whether a reduced MA TDI S’ may affect the symptomatic profile or the overall prognosis of patients with LV diastolic dysfunction.
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Affiliation(s)
- Angel Lopez-Candales
- Cardiovascular Medicine Division, University of Puerto Rico School of Medicine, San Juan, Puerto Rico
| | | | - Francisco Lopez Menendez
- Division of Cardiovascular Health and Disease, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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Assessment of Longitudinal Shortening in Cardiomyopathies with Cardiac Magnetic Resonance. CURRENT CARDIOVASCULAR IMAGING REPORTS 2017. [DOI: 10.1007/s12410-017-9429-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Agger P, Stephenson RS, Dobrzynski H, Atkinson A, Iaizzo PA, Anderson RH, Jarvis JC, Allan SL, Partridge JB, Zhao J, Zhang H, MacIver DH. Insights from echocardiography, magnetic resonance imaging, and microcomputed tomography relative to the mid-myocardial left ventricular echogenic zone. Echocardiography 2016; 33:1546-1556. [DOI: 10.1111/echo.13324] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Peter Agger
- Department of Cardiothoracic and Vascular Surgery; Deptartment of Clinical Medicine; Aarhus University Hospital; Aarhus Denmark
| | - Robert S. Stephenson
- Research Institute for Sport and Exercise Sciences; Liverpool John Moores University; Liverpool United Kingdom
- School of Dentistry; The University of Central Lancashire; Preston United Kingdom
| | - Halina Dobrzynski
- School of Medicine; University of Manchester; Manchester United Kingdom
| | - Andrew Atkinson
- School of Medicine; University of Manchester; Manchester United Kingdom
| | - Paul A. Iaizzo
- Institute for Engineering in Medicine; Department of Surgery; University of Minnesota; Minneapolis Minnesota
| | - Robert H. Anderson
- Institute of Genetic Medicine; Newcastle University; Newcastle Upon Tyne United Kingdom
- Division of Biomedical Sciences; University College London; London United Kingdom
| | - Jonathan C. Jarvis
- Research Institute for Sport and Exercise Sciences; Liverpool John Moores University; Liverpool United Kingdom
| | - Sarah L. Allan
- Department of Cardiology; Taunton & Somerset Hospital; Taunton United Kingdom
| | - John B. Partridge
- Eurobodalla Unit; Rural Clinical School of the ANU College of Medicine, Biology & Environment; Batemans Bay NSW Australia
| | - Jichao Zhao
- Auckland Bioengineering Institute; University of Auckland; Auckland New Zealand
| | - Henggui Zhang
- Biological Physics Group; School of Astronomy and Physics; University of Manchester; Manchester United Kingdom
| | - David H. MacIver
- Department of Cardiology; Taunton & Somerset Hospital; Taunton United Kingdom
- Biological Physics Group; School of Astronomy and Physics; University of Manchester; Manchester United Kingdom
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MacIver DH, Adeniran I, MacIver IR, Revell A, Zhang H. Physiological mechanisms of pulmonary hypertension. Am Heart J 2016; 180:1-11. [PMID: 27659877 DOI: 10.1016/j.ahj.2016.07.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Accepted: 07/05/2016] [Indexed: 12/25/2022]
Abstract
Pulmonary hypertension is usually related to obstruction of pulmonary blood flow at the level of the pulmonary arteries (eg, pulmonary embolus), pulmonary arterioles (idiopathic pulmonary hypertension), pulmonary veins (pulmonary venoocclusive disease) or mitral valve (mitral stenosis and regurgitation). Pulmonary hypertension is also observed in heart failure due to left ventricle myocardial diseases regardless of the ejection fraction. Pulmonary hypertension is often regarded as a passive response to the obstruction to pulmonary flow. We review established fluid dynamics and physiology and discuss the mechanisms underlying pulmonary hypertension. The important role that the right ventricle plays in the development and maintenance of pulmonary hypertension is discussed. We use principles of thermodynamics and discuss a potential common mechanism for a number of disease states, including pulmonary edema, through adding pressure energy to the pulmonary circulation.
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Affiliation(s)
- David H MacIver
- Biological Physics Group, School of Physics & Astronomy, University of Manchester, Manchester, United Kingdom; Department of Cardiology, Taunton & Somerset Hospital, Musgrove Park, Taunton, United Kingdom; Medical Education, University of Bristol, Senate House, Tyndall Avenue, Bristol, United Kingdom.
| | - Ismail Adeniran
- Biological Physics Group, School of Physics & Astronomy, University of Manchester, Manchester, United Kingdom
| | - Iain R MacIver
- Biological Physics Group, School of Physics & Astronomy, University of Manchester, Manchester, United Kingdom
| | - Alistair Revell
- Modelling & Simulation Centre, School of Mechanical, Aerospace & Civil Engineering, University of Manchester, United Kingdom
| | - Henggui Zhang
- Biological Physics Group, School of Physics & Astronomy, University of Manchester, Manchester, United Kingdom
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Contractile Dysfunction in Sarcomeric Hypertrophic Cardiomyopathy. J Card Fail 2016; 22:731-7. [DOI: 10.1016/j.cardfail.2016.03.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 03/06/2016] [Accepted: 03/18/2016] [Indexed: 12/29/2022]
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The mechanism of reduced longitudinal left ventricular systolic function in hypertensive patients with normal ejection fraction. J Hypertens 2015; 33:1962-9; discussion 1969. [DOI: 10.1097/hjh.0000000000000624] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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10
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MacIver DH, Adeniran I, Zhang H. Left ventricular ejection fraction is determined by both global myocardial strain and wall thickness. IJC HEART & VASCULATURE 2015; 7:113-118. [PMID: 28785658 PMCID: PMC5497228 DOI: 10.1016/j.ijcha.2015.03.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 10/08/2014] [Accepted: 03/31/2015] [Indexed: 01/13/2023]
Abstract
Objectives The purpose of this study was to determine the mathematical relationship between left ventricular ejection fraction and global myocardial strain. A reduction in myocardial strain would be expected to cause a fall in ejection fraction. However, there is abundant evidence that abnormalities of myocardial strain can occur with a normal ejection fraction. Explanations such as a compensatory increase in radial or circumferential strain are not supported by clinical studies. We set out to determine the biomechanical relationship between ejection fraction, wall thickness and global myocardial strain. Methods The study used an established abstract model of left ventricular contraction to examine the effect of global myocardial strain and wall thickness on ejection fraction. Equations for the relationship between ejection fraction, wall thickness and myocardial strain were obtained using curve fitting methods. Results The mathematical relationship between ejection fraction, ventricular wall thickness and myocardial strain was derived as follows: φ = e(0.14Ln(ε) + 0.06)ω + (0.9Ln(ε) + 1.2), where φ is ejection fraction (%), ω is wall thickness (cm) and ε is myocardial strain (−%). Conclusion The findings of this study explain the coexistence of reduced global myocardial strain and normal ejection fraction seen in clinical observational studies. Our understanding of the pathophysiological processes in heart failure and associated conditions is substantially enhanced. These results provide a much better insight into the biophysical inter-relationship between myocardial strain and ejection fraction. This improved understanding provides an essential foundation for the design and interpretation of future clinical mechanistic and prognostic studies. Ejection fraction has a limited value in predicting mortality and functional capacity. Myocardial mechanics including the relationship between myocardial strain and ejection fraction are currently poorly understood. We showed that there is biophysical relationship between end-diastolic wall thickness, myocardial strain and ejection fraction. Such a relationship explains the poor correlation of ejection fraction with prognosis and functional capacity. The study provides the foundation for determining the relationship between ventricular hypertrophy, ejection fraction and prognosis. words
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Affiliation(s)
- David H MacIver
- Biological Physics Group, School of Physics & Astronomy, University of Manchester, Manchester, UK.,Department of Cardiology, Taunton & Somerset Hospital, Musgrove Park, Taunton, UK.,Medical Education, University of Bristol, Senate House, Tyndall Avenue, Bristol BS8 1TH, UK
| | - Ismail Adeniran
- Biological Physics Group, School of Physics & Astronomy, University of Manchester, Manchester, UK
| | - Henggui Zhang
- Biological Physics Group, School of Physics & Astronomy, University of Manchester, Manchester, UK
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MacIver DH, Clark AL. The vital role of the right ventricle in the pathogenesis of acute pulmonary edema. Am J Cardiol 2015; 115:992-1000. [PMID: 25697920 DOI: 10.1016/j.amjcard.2015.01.026] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 01/06/2015] [Accepted: 01/06/2015] [Indexed: 11/19/2022]
Abstract
The development of acute pulmonary edema involves a complex interplay between the capillary hydrostatic, interstitial hydrostatic, and oncotic pressures and the capillary permeability. We review the pathophysiological processes involved and illustrate the concepts in a number of common clinical situations including heart failure with normal and reduced ejection fractions, mitral regurgitation, and arrhythmias. We also describe other rarer causes including exercise, swimming, and diving-induced acute pulmonary edema. We suggest a unifying framework in which the critical abnormality is a mismatch or imbalance between the right and left ventricular stroke volumes. In conclusion, we hypothesize that increased right ventricular contraction is an important contributor to the sudden increase in capillary hydrostatic pressure, and therefore, a central mechanism involved in the development of alveolar edema.
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Affiliation(s)
- David H MacIver
- Department of Cardiology, Taunton and Somerset Hospital, Taunton, United Kingdom; Biological Physics Group, School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom; Medical Education, University of Bristol, Bristol, United Kingdom.
| | - Andrew L Clark
- Department of Cardiology, Hull York Medical School, University of Hull, Castle Hill Hospital, Cottingham, United Kingdom
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Adeniran I, MacIver DH, Hancox JC, Zhang H. Abnormal calcium homeostasis in heart failure with preserved ejection fraction is related to both reduced contractile function and incomplete relaxation: an electromechanically detailed biophysical modeling study. Front Physiol 2015; 6:78. [PMID: 25852567 PMCID: PMC4367530 DOI: 10.3389/fphys.2015.00078] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 02/26/2015] [Indexed: 01/08/2023] Open
Abstract
Heart failure with preserved ejection fraction (HFpEF) accounts for about 50% of heart failure cases. It has features of incomplete relaxation and increased stiffness of the left ventricle. Studies from clinical electrophysiology and animal experiments have found that HFpEF is associated with impaired calcium homeostasis, ion channel remodeling and concentric left ventricle hypertrophy (LVH). However, it is still unclear how the abnormal calcium homeostasis, ion channel and structural remodeling affect the electro-mechanical dynamics of the ventricles. In this study we have developed multiscale models of the human left ventricle from single cells to the 3D organ, which take into consideration HFpEF-induced changes in calcium handling, ion channel remodeling and concentric LVH. Our simulation results suggest that at the cellular level, HFpEF reduces the systolic calcium level resulting in a reduced systolic contractile force, but elevates the diastolic calcium level resulting in an abnormal residual diastolic force. In our simulations, these abnormal electro-mechanical features of the ventricular cells became more pronounced with the increase of the heart rate. However, at the 3D organ level, the ejection fraction of the left ventricle was maintained due to the concentric LVH. The simulation results of this study mirror clinically observed features of HFpEF and provide new insights toward the understanding of the cellular bases of impaired cardiac electromechanical functions in heart failure.
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Affiliation(s)
- Ismail Adeniran
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester Manchester, UK
| | - David H MacIver
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester Manchester, UK ; Department of Cardiology, Taunton and Somerset Hospital Musgrove Park, Taunton, UK
| | - Jules C Hancox
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester Manchester, UK ; School of Physiology and Pharmacology and Cardiovascular Research Laboratories, School of Medical Sciences Bristol, UK
| | - Henggui Zhang
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester Manchester, UK ; School of Computer Science and Technology, Harbin Institute of Technology Harbin, China
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MacIver DH. A new understanding and definition of non-compaction cardiomyopathy using analysis of left ventricular wall mechanics and stresses. Int J Cardiol 2014; 174:819-21. [DOI: 10.1016/j.ijcard.2014.04.141] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 04/12/2014] [Indexed: 12/31/2022]
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MacIver DH, Dayer MJ, Harrison AJI. A general theory of acute and chronic heart failure. Int J Cardiol 2012; 165:25-34. [PMID: 22483252 DOI: 10.1016/j.ijcard.2012.03.093] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2012] [Revised: 03/07/2012] [Accepted: 03/08/2012] [Indexed: 12/13/2022]
Abstract
Current concepts of heart failure propose multiple heterogeneous pathophysiological mechanisms. Recently a theoretical framework for understanding chronic heart failure was suggested. This paper develops this framework to include acute heart failure syndromes. We propose that all acute heart failure syndromes may be understood in terms of a relative fall in left ventricular stroke volume. The initial compensatory mechanism is frequently a tachycardia often resulting in a near normal cardiac output. In more severe forms a fall in cardiac output causes hypotension or cardiogenic shock. In chronic heart failure the stroke volume and cardiac output is returned to normal predominantly through ventricular remodeling or dilatation. Ejection fraction is simply the ratio of stroke volume and end-diastolic volume. The resting stroke volume is predetermined by the tissue's needs; therefore, if the ejection fraction changes, the end-diastolic volume must change in a reciprocal manner. The potential role of the right heart in influencing the presentation of left heart disease is examined. We propose that acute pulmonary edema occurs when the right ventricular stroke volume exceeds left ventricular stroke volume leading to fluid accumulation in the alveoli. The possible role of the right heart in determining pulmonary hypertension and raised filling pressures in left-sided heart disease are discussed. Different clinical scenarios are presented to help clarify these proposed mechanisms and the clinical implications of these theories are discussed. Finally an alternative definition of heart failure is proposed.
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Affiliation(s)
- David H MacIver
- Department of Cardiology, Taunton & Somerset Hospital, Musgrove Park, Taunton TA1 5DA, UK.
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MacIver DH, Dayer MJ. An alternative approach to understanding the pathophysiological mechanisms of chronic heart failure. Int J Cardiol 2012; 154:102-10. [DOI: 10.1016/j.ijcard.2011.05.075] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2010] [Revised: 03/16/2011] [Accepted: 05/13/2011] [Indexed: 11/29/2022]
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MacIver DH. A new method for quantification of left ventricular systolic function using a corrected ejection fraction. EUROPEAN JOURNAL OF ECHOCARDIOGRAPHY 2011; 12:228-34. [DOI: 10.1093/ejechocard/jeq185] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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