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Antúnez-Montes OY, Kocica MJ, Olavarria AS, Corno AF, Millan RA, Rosales CI, Sanchez Aparicio HE. Helical structure of the ventricular myocardium. A narrative review of cardiac mechanics. Echocardiography 2023; 40:161-173. [PMID: 36610038 DOI: 10.1111/echo.15515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 11/24/2022] [Accepted: 12/03/2022] [Indexed: 01/09/2023] Open
Abstract
To date, the ventricular myocardial band is the anatomical-functional model that best explains cardiac mechanics during systolic-diastolic phenomena in the cardiac cycle. The implications of the model fundamentally affect the anatomical interpretation of the ventricular myocardium, giving meaning to the direction that muscle fibers take, turning them into an object of study with potential clinical, imaging, and surgical applications. Re-interpreting the anatomy of the ventricular muscle justifies changes in the physiological interpretation, from its functional focus as a fiber unraveling the mechanical phenomena carried out during systole and diastole. We identify the functioning of the heart from the electrical and hemodynamic point of view, but it is necessary to delve into the mechanics that originate the hemodynamic changes observed flowmetrically, and that manifested during the pathology. In this review, the mechanical phenomena that the myocardium performs in each phase of the cardiac cycle are broken down in detail, emphasizing the physical displacements that each of the muscle segments presents, as well as a vision of their alteration and in which pathologies they are mainly identified. Visually, an anatomical correlation to the echocardiogram is provided, pointing out the direction of the segmental myocardial displacement by the strain velocity vector technique.
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Affiliation(s)
| | - Mladen J Kocica
- UC Clinical Center of Serbia, Clinic for Cardiac Surgery, Belgrade, Serbia
| | | | - Antonio Francesco Corno
- Children's Heart Institute, Memorial Hermann Children's Hospital, McGovern Medical School, UTHealth in Houston, Texas, USA
| | - Rocio Aceves Millan
- Echocardiography Section, November 20 National Medical Center, ISSSTE, Mexico City, Mexico
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Izem O, Mourot L, Tordi N, Grandperrin A, Obert P, Rupp T, Nottin S. Key role of left ventricular untwisting in endurance cyclists at onset of exercise. J Appl Physiol (1985) 2021; 131:1565-1574. [PMID: 34590909 DOI: 10.1152/japplphysiol.00907.2020] [Citation(s) in RCA: 2] [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
The rise in oxygen consumption during the transition from rest to exercise is faster in those who are endurance-trained than those who have sedentary lifestyles, partly due to a more efficient cardiac response. However, data regarding this acute cardiac response in trained individuals are limited to heart rate (HR), stroke volume, and cardiac output. Considering this, we compared cardiac kinetics, including left ventricular (LV) strains and twist/untwist mechanics, between endurance-trained cyclists and their sedentary counterparts. Twenty young, male, trained cyclists and 23 untrained participants aged 18-25 yr performed five similar constant workload exercises on a cyclo-ergometer (target HR: 130 beats/min). During each session, LV myocardial diastolic and systolic linear strains, as well as torsional mechanics, were assessed using speckle-tracking echocardiography. Cardiac function was evaluated every 15 s during the first minute and every 30 s thereafter, until 240 s. Stroke volume increased during the first 30-45 s in both groups but to a significantly greater extent in trained cyclists (31% vs. 24%). Systolic parameters were similar in both groups. Transmitral peak filling velocity and peak filling rate responded faster to exercise and with greater amplitude in trained cyclists. Left ventricular filling pressure was lower in the former, whereas LV relaxation was greater but only at the base of the left ventricle. Basal rotation and peak untwisting rate responded faster and to a greater extent in the cyclists. This study provides new mechanical insights into the key role of LV untwisting in the more efficient acute cardiac response of endurance-trained athletes at onset of exercise.NEW & NOTEWORTHY Our study assessed for the first time, to our knowledge, the kinetics of left ventricular function during the transition from rest to constant-load exercise in endurance-trained subjects. We observed a faster cardiac response in cyclists characterized by a faster response of cardiac output, left ventricular transmitral filling, basal rotation, and untwisting. This study highlighted the key role of left ventricular twisting mechanics in the more efficient acute cardiac response of endurance-trained athletes at onset of exercise.
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Affiliation(s)
| | - Laurent Mourot
- University of Bourgogne Franche-Comté, Besançon, France.,Tomsk Polytechnic University, Tomsk, Russia
| | - Nicolas Tordi
- University of Bourgogne Franche-Comté, Besançon, France
| | | | | | - Thomas Rupp
- LIBM, Inter-university Laboratory of Human Movement Science, University Savoie Mont Blanc, Chambéry, France
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Antúnez Montes OY. Correlación anatómica de la estructura helicoidal del miocardio ventricular mediante ecocardiografía. Rev Esp Cardiol 2020. [DOI: 10.1016/j.recesp.2018.10.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Antúnez Montes OY. Anatomical Correlation of the Helical Structure of the Ventricular Myocardium Through Echocardiography. ACTA ACUST UNITED AC 2019; 73:153-160. [PMID: 31000468 DOI: 10.1016/j.rec.2018.10.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 10/23/2018] [Indexed: 01/14/2023]
Abstract
INTRODUCTION AND OBJECTIVES The helical structure of the ventricular myocardium provides a simple view of cardiac anatomy, based on physiological evidence that has been broadly demonstrated in experimental and imaging studies, and helps to explain the electromechanical contraction of the myocardium during the cardiac cycle. The aim of this study was to standardize and provide a detailed description of the technique for preparing and manually dissecting the myocardium proposed empirically by Torrent-Guasp. A further aim was to anatomically and topographically correlate the helical band with echocardiographic long-axis, short-axis, and 4-chamber projections. METHODS We dissected 42 hearts-20 bovine, 20 porcine and 2 human hearts-to standardize the myocardial dissection technique. Subsequently, the distinct segments were color coded to correlate the anatomical specimens with echocardiographic projections. RESULTS Loss of 38% of the myocardial mass after boiling was sufficient to standardize myocardial dissection and allowed an efficient technique. No morphological differences were found between the bands of the hearts studied. The 4 myocardial segments could be identified in the echocardiographic projections. CONCLUSIONS Standardization of the technique is useful to dissect any type of heart. Echocardiography is useful to assess the distinct segments that compose the myocardium. More research is needed to generate practical applications of this knowledge to echocardiography and other fields.
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Mora V, Roldán I, Romero E, Saurí A, Romero D, Pérez-Gozalbo J, Ugalde N, Bertolín J, Rodriguez-Israel M, Delgado CPO, Lowenstein JA. Myocardial Contraction during the Diastolic Isovolumetric Period: Analysis of Longitudinal Strain by Means of Speckle Tracking Echocardiography. J Cardiovasc Dev Dis 2018; 5:E41. [PMID: 30096870 PMCID: PMC6162423 DOI: 10.3390/jcdd5030041] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 08/02/2018] [Accepted: 08/04/2018] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND According to the ventricular myocardial band model, the diastolic isovolumetric period is a contraction phenomenon. Our objective was to employ speckle-tracking echocardiography (STE) to analyze myocardial deformation of the left ventricle (LV) and to confirm if it supports the myocardial band model. METHODS This was a prospective observational study in which 90 healthy volunteers were recruited. We evaluated different types of postsystolic shortening (PSS) from an LV longitudinal strain study. Duration of latest deformation (LD) was calculated as the time from the start of the QRS complex of the ECG to the latest longitudinal deformation peak in the 18 segments of the LV. RESULTS The mean age of our subjects was 50.3 ± 11.1 years. PSS was observed in 48.4% of the 1620 LV segments studied (19.8%, 13.5%, and 15.1% in the basal, medial, and apical regions, respectively). PSS was more frequent in the basal, medial septal, and apical anteroseptal segments (>50%). LD peaked in the interventricular septum and in the basal segments of the LV. CONCLUSIONS The pattern of PSS and LD revealed by STE suggests there is contraction in the postsystolic phase of the cardiac cycle. The anatomical location of the segments in which this contraction is most frequently observed corresponds to the main path of the ascending component of the myocardial band. This contraction can be attributed to the protodiastolic untwisting of the LV.
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Affiliation(s)
- Vicente Mora
- Department of Cardiology, Hospital Dr Peset, 46017 Valencia, Spain.
| | - Ildefonso Roldán
- Department of Cardiology, Hospital Dr Peset, 46017 Valencia, Spain.
| | - Elena Romero
- Department of Cardiology, Hospital Dr Peset, 46017 Valencia, Spain.
| | - Assumpció Saurí
- Department of Cardiology, Hospital Dr Peset, 46017 Valencia, Spain.
| | - Diana Romero
- Cardiodiagnosis Department, Medical Research of Buenos Aires, CP 1425 Buenos Aires, Argentina.
| | | | - Natalia Ugalde
- Cardiodiagnosis Department, Medical Research of Buenos Aires, CP 1425 Buenos Aires, Argentina.
| | - Javier Bertolín
- Department of Cardiology, Hospital Dr Peset, 46017 Valencia, Spain.
| | - Melisa Rodriguez-Israel
- Cardiodiagnosis Department, Medical Research of Buenos Aires, CP 1425 Buenos Aires, Argentina.
| | | | - Jorge A Lowenstein
- Cardiodiagnosis Department, Medical Research of Buenos Aires, CP 1425 Buenos Aires, Argentina.
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Buckberg GD, Hoffman JI, Coghlan HC, Nanda NC. Ventricular structure–function relations in health and disease: Part I. The normal heart. Eur J Cardiothorac Surg 2014; 47:587-601. [DOI: 10.1093/ejcts/ezu278] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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Cosín Aguilar J, Hernándiz Martínez A. The band arrangement of myocardial fibres determines cardiac morphology and function. ACTA ACUST UNITED AC 2014; 66:768-70. [PMID: 24773855 DOI: 10.1016/j.rec.2013.05.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 05/06/2013] [Indexed: 12/01/2022]
Affiliation(s)
- Juan Cosín Aguilar
- Unidad de Cardiocirculatorio, Centro de Investigación, Hospital Universitario La Fe, Valencia, Spain
| | - Amparo Hernándiz Martínez
- Unidad de Cardiocirculatorio, Centro de Investigación, Hospital Universitario La Fe, Valencia, Spain.
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Cosín Aguilar J, Hernándiz Martínez A. La disposición de las fibras miocárdicas en una banda condiciona la morfología y la función del corazón. Rev Esp Cardiol 2013. [DOI: 10.1016/j.recesp.2013.05.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Vortices formed on the mitral valve tips aid normal left ventricular filling. Ann Biomed Eng 2013; 41:1049-61. [PMID: 23389556 DOI: 10.1007/s10439-013-0755-0] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2012] [Accepted: 01/23/2013] [Indexed: 10/27/2022]
Abstract
For the left ventricle (LV) to function as an effective pump it must be able to fill from a low left atrial pressure. However, this ability is lost in patients with heart failure. We investigated LV filling by measuring the cardiac blood flow using 2D phase contrast magnetic resonance imaging and quantified the intraventricular pressure gradients and the strength and location of vortices. In normal subjects, blood flows towards the apex prior to the mitral valve opening, and the mitral annulus moves rapidly away after the valve opens, with both effects enhancing the vortex ring at the mitral valve tips. Instead of being a passive by-product of the process as was previously believed, this ring facilitates filling by reducing convective losses and enhancing the function of the LV as a suction pump. The virtual channel thus created by the vortices may help insure efficient mass transfer for the left atrium to the LV apex. Impairment of this mechanism contributes to diastolic dysfunction, with LV filling becoming dependent on left atrial pressure, which can lead to eventual heart failure. Better understanding of the mechanics of this progression may lead to more accurate diagnosis and treatment of this disease.
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Koh C, Hong WJ, Yung TC, Lun KS, Wong SJ, Cheung YF. Left ventricular torsional mechanics and diastolic function in congenital heart block with right ventricular pacing. Int J Cardiol 2012; 160:31-5. [DOI: 10.1016/j.ijcard.2011.03.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 02/08/2011] [Accepted: 03/08/2011] [Indexed: 10/18/2022]
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Burns KV, Kaufman CL, Kelly AS, Parah JS, Dengel DR, Bank AJ. Torsion and Dyssynchrony Differences Between Chronically Paced and Non-Paced Heart Failure Patients. J Card Fail 2011; 17:495-502. [DOI: 10.1016/j.cardfail.2011.02.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Revised: 02/22/2011] [Accepted: 02/24/2011] [Indexed: 11/27/2022]
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Cazorla O, Lacampagne A. Regional variation in myofilament length-dependent activation. Pflugers Arch 2011; 462:15-28. [DOI: 10.1007/s00424-011-0933-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Revised: 02/01/2011] [Accepted: 02/03/2011] [Indexed: 12/17/2022]
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Gao C, Ye W, Li L. Three-dimension structure of ventricular myocardial fibers after myocardial infarction. J Cardiothorac Surg 2010; 5:116. [PMID: 21092295 PMCID: PMC2999601 DOI: 10.1186/1749-8090-5-116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Accepted: 11/23/2010] [Indexed: 11/10/2022] Open
Abstract
Background To explore the pathological changes of three-dimension structure of ventricular myocardial fibers after anterior myocardial infarction in dog heart. Methods Fourteen acute anterior myocardial infarction models were made from healthy dogs (mean weight 17.6 ± 2.5 kg). Six out of 14 dogs with old myocardial infarction were sacrificed, and their hearts were harvested after they survived the acute anterior myocardial infarction for 3 months. Each heart was dissected into ventricular myocardial band (VMB), morphological characters in infarction region were observed, and infarct size percents in descending segment and ascending segment were calculated. Results Six dog hearts were successfully dissected into VMB. Uncorresponding damages in myocardial fibers of descending segment and ascending segment were found in apical circle in anterior wall infarction. Infarct size percent in the ascending segment was significantly larger than that in the descending segment (23.36 ± 3.15 (SD) vs 30.69 ± 2.40%, P = 0.0033); the long axis of infarction area was perpendicular to the orientation of myocardial fibers in ascending segment; however, the long axis of the infarction area was parallel with the orientation of myocardial fibers in descending segment. Conclusions We found that damages were different in both morphology and size in ascending segment and descending segment in heart with myocardial infarction. This may provide an important insight for us to understand the mechanism of heart failure following coronary artery diseases.
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Affiliation(s)
- Changqing Gao
- Department of Cardiovascular Surgery, PLA General Hospital, 28 Fuxing Road, Beijing 100853, PR China.
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Cosín Aguilar JA, Hernándiz Martínez A, Tuzón Segarra MT, Agüero Ramón-Llin J, Torrent-Guasp F. Experimental study of the so called left ventricular isovolumic relaxation phase. Rev Esp Cardiol 2009; 62:392-9. [PMID: 19401124 DOI: 10.1016/s1885-5857(09)71666-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
INTRODUCTION AND OBJECTIVES Left ventricular filling begins in the ventricular isovolumic relaxation phase. According to the Torrent-Guasp myocardial band theory, this phase results from the contraction of the final portion of the myocardial band: the ascending segment of the apical loop. The objectives were to study the myocardial mechanisms influencing transmitral flow during early diastole and to determine whether the rapid ventricular filling phase involves contraction or relaxation. METHODS An experimental in vivo pig model was used. Regional contractility in three segments of the myocardial band was assessed using piezoelectric crystals and mitral flow was measured by echo-Doppler ultrasonography at baseline and after akinesia had been induced in the ascending segment by 2.5% formaldehyde infusion. Changes in intracavitary pressure in the left ventricle and left atrium and flow alterations in the aortic root were recorded. The start of the isovolumic relaxation phase was identified using the time at which the ejection of blood ceases, as indicated by aortic flow measurements. RESULTS During the left ventricular isovolumetric relaxation phase, the ascending segment of the apical loop was undergoing contraction. The infusion of formaldehyde into this segment affected the extent to which the intraventricular pressure could decrease, prolonged the isovolumic relaxation phase and resulted in a lower minimum pressure. It also produced a significant decrease in transmitral flow velocity in early diastole and an increase at end-diastole. CONCLUSIONS The rapid ventricular filling phase is characterized by contraction.
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Affiliation(s)
- Juan A Cosín Aguilar
- Unidad de Cardiología Experimental, Centro de Investigación, Hospital Universitario La Fe, Avda. Campanar 21, Valencia 46009, Spain.
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Niederer SA, Smith NP. The role of the Frank-Starling law in the transduction of cellular work to whole organ pump function: a computational modeling analysis. PLoS Comput Biol 2009; 5:e1000371. [PMID: 19390615 PMCID: PMC2668184 DOI: 10.1371/journal.pcbi.1000371] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Accepted: 03/20/2009] [Indexed: 12/01/2022] Open
Abstract
We have developed a multi-scale biophysical electromechanics model of the rat left ventricle at room temperature. This model has been applied to investigate the relative roles of cellular scale length dependent regulators of tension generation on the transduction of work from the cell to whole organ pump function. Specifically, the role of the length dependent Ca(2+) sensitivity of tension (Ca(50)), filament overlap tension dependence, velocity dependence of tension, and tension dependent binding of Ca(2+) to Troponin C on metrics of efficient transduction of work and stress and strain homogeneity were predicted by performing simulations in the absence of each of these feedback mechanisms. The length dependent Ca(50) and the filament overlap, which make up the Frank-Starling Law, were found to be the two dominant regulators of the efficient transduction of work. Analyzing the fiber velocity field in the absence of the Frank-Starling mechanisms showed that the decreased efficiency in the transduction of work in the absence of filament overlap effects was caused by increased post systolic shortening, whereas the decreased efficiency in the absence of length dependent Ca(50) was caused by an inversion in the regional distribution of strain.
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Cosín Aguilar JA, Hernándiz Martínez A, Teresa Tuzón Segarra M, Ramón-Llin JA, Torrent-Guasp F. Estudio experimental de la llamada fase de relajación isovolumétrica del ventrículo izquierdo. Rev Esp Cardiol 2009. [DOI: 10.1016/s0300-8932(09)70896-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Abstract
The keynote to understanding cardiac function is recognizing the underlying architecture responsible for the contractile mechanisms that produce the narrowing, shortening, lengthening, widening, and twisting disclosed by echocardiographic and magnetic resonance technology. Despite background knowledge of a spiral clockwise and counterclockwise arrangement of muscle fibers, issues about the exact architecture, interrelationships, and function of the different sets of muscle fibers remain to be resolved. This report (1) details observed patterns of cardiac dynamic directional and twisting motions via multiple imaging sources; (2) summarizes the deficiencies of correlations between ventricular function and known ventricular muscle architecture; (3) correlates known cardiac motions with the functional anatomy within the helical ventricular myocardial band; and (4) defines an innovative muscular systolic mechanism that challenges the previously described concept of “isovolumic relaxation.” This new knowledge may open new doors to treating heart failure due to diastolic dysfunction.
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Affiliation(s)
- Gerald Buckberg
- From the Departments of Cardiothoracic Surgery (G.B.), Medicine (S.S.), and Anesthesiology (A.M.), David Geffen School of Medicine at UCLA, Los Angeles, Calif; Department of Pediatrics and Cardiovascular Research Institute, University of California at San Francisco, San Francisco (J.I.E.H.); and Division of Cardiovascular Diseases, University of Alabama at Birmingham, Birmingham (C.C.)
| | - Julien I.E. Hoffman
- From the Departments of Cardiothoracic Surgery (G.B.), Medicine (S.S.), and Anesthesiology (A.M.), David Geffen School of Medicine at UCLA, Los Angeles, Calif; Department of Pediatrics and Cardiovascular Research Institute, University of California at San Francisco, San Francisco (J.I.E.H.); and Division of Cardiovascular Diseases, University of Alabama at Birmingham, Birmingham (C.C.)
| | - Aman Mahajan
- From the Departments of Cardiothoracic Surgery (G.B.), Medicine (S.S.), and Anesthesiology (A.M.), David Geffen School of Medicine at UCLA, Los Angeles, Calif; Department of Pediatrics and Cardiovascular Research Institute, University of California at San Francisco, San Francisco (J.I.E.H.); and Division of Cardiovascular Diseases, University of Alabama at Birmingham, Birmingham (C.C.)
| | - Saleh Saleh
- From the Departments of Cardiothoracic Surgery (G.B.), Medicine (S.S.), and Anesthesiology (A.M.), David Geffen School of Medicine at UCLA, Los Angeles, Calif; Department of Pediatrics and Cardiovascular Research Institute, University of California at San Francisco, San Francisco (J.I.E.H.); and Division of Cardiovascular Diseases, University of Alabama at Birmingham, Birmingham (C.C.)
| | - Cecil Coghlan
- From the Departments of Cardiothoracic Surgery (G.B.), Medicine (S.S.), and Anesthesiology (A.M.), David Geffen School of Medicine at UCLA, Los Angeles, Calif; Department of Pediatrics and Cardiovascular Research Institute, University of California at San Francisco, San Francisco (J.I.E.H.); and Division of Cardiovascular Diseases, University of Alabama at Birmingham, Birmingham (C.C.)
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Sengupta PP, Tondato F, Khandheria BK, Belohlavek M, Jahangir A. Electromechanical Activation Sequence in Normal Heart. Heart Fail Clin 2008; 4:303-14. [DOI: 10.1016/j.hfc.2008.02.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Sengupta PP, Krishnamoorthy VK, Korinek J, Narula J, Vannan MA, Lester SJ, Tajik JA, Seward JB, Khandheria BK, Belohlavek M. Left ventricular form and function revisited: applied translational science to cardiovascular ultrasound imaging. J Am Soc Echocardiogr 2007; 20:539-51. [PMID: 17485001 PMCID: PMC1951787 DOI: 10.1016/j.echo.2006.10.013] [Citation(s) in RCA: 228] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2006] [Indexed: 02/08/2023]
Abstract
Doppler tissue imaging (DTI) and DTI-derived strain imaging are robust physiologic tools used for the noninvasive assessment of regional myocardial function. As a result of high temporal and spatial resolution, regional function can be assessed for each phase of the cardiac cycle and within the transmural layers of the myocardial wall. Newer techniques that measure myocardial motion by speckle tracking in gray-scale images have overcome the angle dependence of DTI strain, allowing for measurement of 2-dimensional strain and cardiac rotation. DTI, DTI strain, and speckle tracking may provide unique information that deciphers the deformation sequence of complexly oriented myofibers in the left ventricular wall. The data are, however, limited. This review examines the structure and function of the left ventricle relative to the potential clinical application of DTI and speckle tracking in assessing the global mechanical sequence of the left ventricle in vivo.
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Affiliation(s)
- Partho P Sengupta
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, USA
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Martins AS, Silva MADM, Padovani CR, Matsubara BB, Braile DM, Catâneo AJM. Myocardial protection by continuous, blood, antegrade-retrograde cardioplegia in rabbits. Acta Cir Bras 2007; 22:43-6. [PMID: 17293949 DOI: 10.1590/s0102-86502007000100008] [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: 11/22/2022] Open
Abstract
PURPOSE To study the effectiveness of the continuous, blood, antegrade-retrograde cardioplegia in an experimental model of isolated heart, evaluating ventricular function. METHODS Rabbits were divided into four groups: Control--C(n=10); ischemic crystalloid cardioplegia--IC(n=10); ischemic blood cardioplegia--IB(n=10); ischemic non cardioplegia--INC(n=10). After the ischemic protocol period the ventricular function was analyzed by the intra-ventricular balloon technique. RESULTS the intra-ventricular developed pressure (IVDP) was: C(92.90 +/- 6.86mmHg); IC(77.78 +/- 6.15mmHg); IB(93.64 +/- 5.09mmHg); INC(39.46 +/- 8.91mmHg) p< 0.005. The first derivative of intra-ventricular pressure in its positive deflection was: C(1137.50 +/- 92.23mmHg/sec); IC(1130.62 +/- 43.78mmHg/sec); IB(1187.58 +/- 88.38mmHg/sec); INC(620.02 +/- 43.80mmHg/se) p<0.005. The first derivate pressure in its negative deflection was: C(770.00 +/- 73.41mmHg/sec); IC(610.03 +/- 47.43mmg/sec); IB(762.53 +/- 46.02mmHg/sec); INC(412.35 +/- 84.36mmHg/sec) p< 0,005. The stress-strain angular logarithmic coefficient was: C(0.108 +/- 0.02); IC(0.159 +/- 0.038); IB(0.114 +/- 0.016); INC(0.175 +/- 0.038) p< 0.05. CONCLUSION The ischemic group protected by blood cardioplegia showed better ventricular function than ischemic group protected by crystalloid cardioplegia and the non protected group.
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Affiliation(s)
- Antônio Sérgio Martins
- Surgical Research Laboratory, Botucatu Faculty of Medicine, State University of São Paulo, 18.618-000 Botucatu, SP, Brazil.
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Ashikaga H, Coppola BA, Hopenfeld B, Leifer ES, McVeigh ER, Omens JH. Transmural dispersion of myofiber mechanics: implications for electrical heterogeneity in vivo. J Am Coll Cardiol 2007; 49:909-16. [PMID: 17320750 PMCID: PMC2572715 DOI: 10.1016/j.jacc.2006.07.074] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2006] [Revised: 07/05/2006] [Accepted: 07/10/2006] [Indexed: 10/23/2022]
Abstract
OBJECTIVES We investigated whether transmural mechanics could yield insight into the transmural electrical sequence. BACKGROUND Although the concept of transmural dispersion of repolarization has helped explain a variety of arrhythmias, its presence in vivo is still disputable. METHODS We studied the time course of transmural myofiber mechanics in the anterior left ventricle of normal canines in vivo (n = 14) using transmural bead markers under biplane cineradiography. In 4 of these animals, plunge electrodes were placed in the myocardial tissue within the bead set to measure transmural electrical sequence. RESULTS The onset of myofiber shortening was earliest at endocardial layers and progressively delayed toward epicardial layers (p < 0.001), resulting in transmural dispersion of myofiber shortening of 39 ms. The onset of myofiber relaxation was earliest at epicardial layers and most delayed at subendocardial layers (p = 0.004), resulting in transmural dispersion of myofiber relaxation of 83 ms. There was no significant transmural gradient in electrical repolarization (p = NS). CONCLUSIONS Despite lack of evidence of significant transmural gradient in electrical repolarization in vivo, there is transmural dispersion of myofiber relaxation as well as shortening.
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Affiliation(s)
- Hiroshi Ashikaga
- Department of Medicine and Bioengineering, University of California, San Diego, La Jolla, California, USA.
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Stelzer JE, Moss RL. Contributions of stretch activation to length-dependent contraction in murine myocardium. ACTA ACUST UNITED AC 2007; 128:461-71. [PMID: 17001086 PMCID: PMC2151573 DOI: 10.1085/jgp.200609634] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The steep relationship between systolic force production and end diastolic volume (Frank-Starling relationship) in myocardium is a potentially important mechanism by which the work capacity of the heart varies on a beat-to-beat basis, but the molecular basis for the effects of myocardial fiber length on cardiac work are still not well understood. Recent studies have suggested that an intrinsic property of myocardium, stretch activation, contributes to force generation during systolic ejection in myocardium. To examine the role of stretch activation in length dependence of activation we recorded the force responses of murine skinned myocardium to sudden stretches of 1% of muscle length at both short (1.90 μm) and long (2.25 μm) sarcomere lengths (SL). Maximal Ca2+-activated force and Ca2+ sensitivity of force were greater at longer SL, such that more force was produced at a given Ca2+ concentration. Sudden stretch of myocardium during an otherwise isometric contraction resulted in a concomitant increase in force that quickly decayed to a minimum and was followed by a delayed development of force, i.e., stretch activation, to levels greater than prestretch force. At both maximal and submaximal activations, increased SL significantly reduced the initial rate of force decay following stretch; at submaximal activations (but not at maximal) the rate of delayed force development was accelerated. This combination of mechanical effects of increased SL would be expected to increase force generation during systolic ejection in vivo and prolong the period of ejection. These results suggest that sarcomere length dependence of stretch activation contributes to the steepness of the Frank-Starling relationship in living myocardium.
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Affiliation(s)
- Julian E Stelzer
- Department of Physiology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA.
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Narula J, Vannan MA, DeMaria AN. Of That Waltz in My Heart⁎†⁎Editorials published in the Journal of the American College of Cardiologyreflect the views of the authors and do not necessarily represent the views of JACCor the American College of Cardiology.†From the London musical “The Dancing Years” (1939), Ivor Novello and Christopher Hassall. J Am Coll Cardiol 2007; 49:917-20. [PMID: 17320751 DOI: 10.1016/j.jacc.2006.12.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Indexed: 10/23/2022]
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Sengupta PP, Korinek J, Belohlavek M, Narula J, Vannan MA, Jahangir A, Khandheria BK. Left ventricular structure and function: basic science for cardiac imaging. J Am Coll Cardiol 2006; 48:1988-2001. [PMID: 17112989 DOI: 10.1016/j.jacc.2006.08.030] [Citation(s) in RCA: 325] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2006] [Revised: 08/29/2006] [Accepted: 08/30/2006] [Indexed: 12/11/2022]
Abstract
The myofiber geometry of the left ventricle (LV) changes gradually from a right-handed helix in the subendocardium to a left-handed helix in the subepicardium. In this review, we associate the LV myofiber architecture with emerging concepts of the electromechanical sequence in a beating heart. We discuss: 1) the morphogenesis and anatomical arrangement of muscle fibers in the adult LV; 2) the sequence of depolarization and repolarization; 3) the physiological inhomogeneity of transmural myocardial mechanics and the apex-to-base sequence of longitudinal and circumferential deformation; 4) the sequence of LV rotation; and 5) the link between LV deformation and the intracavitary flow direction observed during each phase of the cardiac cycle. Integrating the LV structure with electrical activation and motion sequences observed in vivo provides an understanding about the spatiotemporal sequence of regional myocardial performance that is essential for noninvasive cardiac imaging.
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Affiliation(s)
- Partho P Sengupta
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, USA
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Stelzer JE, Patel JR, Moss RL. Protein kinase A-mediated acceleration of the stretch activation response in murine skinned myocardium is eliminated by ablation of cMyBP-C. Circ Res 2006; 99:884-90. [PMID: 16973906 DOI: 10.1161/01.res.0000245191.34690.66] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Beta-adrenergic agonists induce protein kinase A (PKA) phosphorylation of the cardiac myofilament proteins myosin binding protein C (cMyBP-C) and troponin I (cTnI), resulting in enhanced systolic function, but the relative contributions of cMyBP-C and cTnI to augmented contractility are not known. To investigate possible roles of cMyBP-C in this response, we examined the effects of PKA treatment on the rate of force redevelopment and the stretch activation response in skinned ventricular myocardium from both wild-type (WT) and cMyBP-C null (cMyBP-C(-/-)) myocardium. In WT myocardium, PKA treatment accelerated the rate of force redevelopment and the stretch activation response, resulting in a shorter time to the peak of delayed force development when the muscle was stretched to a new isometric length. Ablation of cMyBP-C accelerated the rate of force redevelopment and stretch activation response to a degree similar to that observed in PKA treatment of WT myocardium; however, PKA treatment had no effect on the rate of force development and the stretch activation response in null myocardium. These results indicate that ablation of cMyBP-C and PKA treatment of WT myocardium have similar effects on cross-bridge cycling kinetics and suggest that PKA phosphorylation of cMyBP-C accelerates the rate of force generation and thereby contributes to the accelerated twitch kinetics observed in living myocardium during beta-adrenergic stimulation.
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Affiliation(s)
- Julian E Stelzer
- Department of Physiology, University of Wisconsin Medical School, 1300 University Ave, Madison, WI 53706, USA.
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