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Effect of cardiac ventricular mechanical contraction on the characteristics of the ECG: A simulation study

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DOI: 10.4236/jbise.2013.612A007    3,774 Downloads   5,918 Views   Citations

ABSTRACT

Introduction: The 12-lead electrocardiogram (ECG) is the most widely-used tool for the detection and diagnosis of cardiac conditions including myocardial infarction and ischemia. It has therefore been a focus of cardiac modeling. However, the most contemporary in silico ECG investigations of the intact heart have assumed a static heart and ignored the mechanical contraction that is an essential component of cardiac function. The aim of this study was to utilize electromechanically coupled human ventricle models to explore the consequences of ventricular mechanical contraction on the ECG profiles. Methods and Results: Biophysically detailed human ventricular cell models incorporating contractile activity and a stretchactivated current (Isac) were incorporated into a 3D human ventricular model within a human torso, from which 12-lead ECGs were computed at a stimulation rate of 1 Hz. Compared to the static model, ventricular contraction without Isac had little effect on the QRS complex, but shifted the T-wave peak leftwards and reduced its peak amplitude. With Isac, ventricular mechanical contraction increased the QRS duration by 23% and QT interval by 5%. Conclusion: Mechanical contraction of the heart has a significant effect on the morphology and characteristics of the ECG particularly on the T-wave. The alteration of the cell membrane kinetics by stretch via Isac further exacerbates these effects. Our simulation data suggest that mechanical contraction should be considered in the interpretation of ECGs in pathological conditions, especially those in which mechanical contraction of the heart is impaired.

 

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The authors declare no conflicts of interest.

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Adeniran, I. , Hancox, J. and Zhang, H. (2013) Effect of cardiac ventricular mechanical contraction on the characteristics of the ECG: A simulation study. Journal of Biomedical Science and Engineering, 6, 47-60. doi: 10.4236/jbise.2013.612A007.

References

[1] Drew, B.J., Califf, R.M., Funk, M., Kaufman, E.S., Krucoff, M.W., Laks, M.M., Macfarlane, P.W., Sommargren, C., Swiryn, S., Van Hare, G.F. and American Heart Association (2005) AHA scientific statement: Practice standards for electrocardiographic monitoring in hospital settings: An American Heart Association Scientific Statement from the Councils on Cardiovascular Nursing, Clinical Cardiology, and Cardiovascular Disease in the Young: Endorsed by the International Society of Computerized electrocardiology and the American Association of Critical-Care Nurses. Journal of Cardiovascular Nursing, 20, 76-106.
http://dx.doi.org/10.1097/00005082-200503000-00003
[2] Bonow, R.O., Mann, D.L., Zipes, D.P. and Libby, P. (2011) Braunwald’s heart disease: A textbook of cardiovascular medicine, 2-volume set: Expert consult premium edition-enhanced online features and print. 9th Edition, Saunders.
[3] Malmivuo, J. and Plonsey, R. (1995) Bioelectromagnetism: principles and applications of bioelectric and biomagnetic fields. Oxford University Press, New York.
http://dx.doi.org/10.1093/acprof:oso/9780195058239.001.0001
[4] Menown, I.B., Mackenzie, G. and Adgey, A.A. (2000) Optimizing the initial 12-lead electrocardiographic diagnosis of acute myocardial infarction. European Heart Journal, 21, 275-283.
ttp://dx.doi.org/10.1053/euhj.1999.1748
[5] Brady, W.J., Chan, T.C. and Pollack, M. (2000) Electrocardiographic manifestations: Patterns that confound the EKG diagnosis of acute myocardial infarction-left bundle branch block, ventricular paced rhythm, and left ventricular hypertrophy. Journal of Emergency Medicine, 18, 71-78. http://dx.doi.org/10.1016/S0736-4679(99)00178-X
[6] Sovilj, S., Magjarevic, R., Lovell, N.H. and Dokos, S. (2013) A simplified 3D model of whole heart electrical activity and 12-lead ECG generation. Computational and Mathematical Methods in Medicine, 2013, Article ID: 134208.
[7] Keller, D.U.J, Seemann, G., Weiss, D.L., Farina, D., Zehelein, J. and Dossel, O. (2007) Computer based modeling of the congenital long-QT 2 syndrome in the Visible Man torso: From genes to ECG. Proceedings of the 29th Annual International Conference of the IEEE EMBS, Lyon, 23-26 August 2007, 1410-1413.
[8] Boulakia, M., Cazeau, S., Fernández, M.A., Gerbeau, J.-F. and Zemzemi, N. (2010) Mathematical modeling of electrocardiograms: A numerical study. Annals of Biomedical Engineering, 38, 1071-1097.
http://dx.doi.org/10.1007/s10439-009-9873-0
[9] Potse, M., Dubé, B. and Vinet, A. (2009) Cardiac anisotropy in boundary-element models for the electrocardiogram. Medical & Biological Engineering & Computing, 47, 719-729.
http://dx.doi.org/10.1007/s11517-009-0472-x
[10] Potse, M., Dube, B. and Gulrajani, R.M. (2003) ECG simulations with realistic human membrane, heart, and torso models. Proceedings of the 25th Annual International Conference of the IEEE EMBS, Cancun, 17-21 September 2003, 70-73.
[11] Lab, M.J. (1996) Mechanoelectric feedback (transduction) in heart: Concepts and implications. Cardiovascular Research, 32, 3-14.
[12] Taggart, P. (1996) Mechano-electric feedback in the human heart. Cardiovascular Research, 32, 38-43.
[13] Taggart, P. and Sutton, P.M. (1999) Cardiac mechanoelectric feedback in man: Clinical relevance. Progress in Biophysics and Molecular Biology, 71, 139-154.
http://dx.doi.org/10.1016/S0079-6107(98)00039-X
[14] Kelly, D., Mackenzie, L., Hunter, P., Smaill, B. and Saint, D.A. (2006) Gene expression of stretch-activated channels and mechanoelectric feedback in the heart. Clinical and Experimental Pharmacology and Physiology, 33, 642-648.
http://dx.doi.org/10.1111/j.1440-1681.2006.04392.x
[15] Katz, A. (2010) Physiology of the heart. 5th Edition, Lippincott Williams & Wilkins, Philadelphia.
[16] Franz, M.R. (1996) Mechano-electrical feedback in ventricular myocardium. Cardiovascular Research, 32, 15-24.
[17] Lab, M.J. (1982) Contraction-excitation feedback in myocardium. Physiological basis and clinical relevance. Circulation Research, 50, 757-766.
http://dx.doi.org/10.1161/01.RES.50.6.757
[18] Ward, M.-L. and Allen, D.G. (2010) Stretch-activated channels in the heart: Contribution to cardiac performance. In: Kamkin, A. and Kiseleva, I., Ed., Mechanosensitivity of the Heart Mechanosensitivity in Cells and Tissues, Springer, Dordrecht, 141-167.
[19] Youm, J.B., Han, J., Kim, N., Zhang, Y.-H., Kim, E., Leem, C.H., Kim, S.H. and Earm, Y.E. (2005) Role of stretch-activated channels in the heart: Action potential and Ca2+ transients. In: Kamkin, A. and Kiseleva, I., Ed., Mechanosensitivity in Cells and Tissues, Academia, Moscow.
[20] Belus, A. and White, E. (2003) Streptomycin and intracellular calcium modulate the response of single guineapig ventricular myocytes to axial stretch. The Journal of Physiology, 546, 501-509.
http://dx.doi.org/10.1113/jphysiol.2002.027573
[21] Zeng, T., Bett, G.C. and Sachs, F. (2000) Stretch-activated whole cell currents in adult rat cardiac myocytes. American Journal of Physiology. Heart and Circulatory Physiology, 278, H548-H557.
[22] Dean, J.W. and Lab, M.J. (1989) Effect of changes in load on monophasic action potential and segment length of pig heart in situ. Cardiovascular Research, 23, 887-896. http://dx.doi.org/10.1093/cvr/23.10.887
[23] Franz, M.R., Burkhoff, D., Yue, D.T. and Sagawa, K. (1989) Mechanically induced action potential changes and arrhythmia in isolated and in situ canine hearts. Cardiovascular Research, 23, 213-223.
http://dx.doi.org/10.1093/cvr/23.3.213
[24] Hansen, D.E. (1993) Mechanoelectrical feedback effects of altering preload, afterload, and ventricular shortening. American Journal of Physiology, 264, H423-H432.
[25] O’Hara, T., Virág, L., Varró, A. and Rudy, Y. (2011) Simulation of the undiseased human cardiac ventricular action potential: Model formulation and experimental validation. PLOS Computational Biology, 7, Article ID: e1002061.
http://dx.doi.org/10.1371/journal.pcbi.1002061
[26] Rice, J.J., Wang, F., Bers, D.M. and de Tombe, P.P. (2008) Approximate model of cooperative activation and crossbridge cycling in cardiac muscle using ordinary differential equations. Biophysical Journal, 95, 2368-2390.
http://dx.doi.org/10.1529/biophysj.107.119487
[27] Adeniran, I., Hancox, J. and Zhang, H. (2013) In silico investigation of the short QT syndrome, using human ventricle models incorporating electromechanical coupling. Front Physiology, 4, 166.
[28] Panfilov, A.V., Keldermann, R.H. and Nash, M.P. (2005) Self-organized pacemakers in a coupled reaction-diffusion-mechanics system. Physical Review Letters, 95, Article ID: 258104.
http://dx.doi.org/10.1103/PhysRevLett.95.258104
[29] Lunze, K., Stalhand, J. and Leonhardt, S. (2010) Modeling of stretch-activated sarcolemmal channels in smooth muscle cells. Proceedings of the World Congress on Medical Physics and Biomedical Engineering IFMBE, Munich, 7-12 September 2009, 740-743.
[30] Kuijpers, N.H.L. (2008) Cardiac electrophysiology and mechanoelectric feedback. Ph.D. Thesis, Eindhoven University of Technology, Eindhoven.
[31] Kohl, P. and Sachs, F. (2001) Mechanoelectric feedback in cardiac cells. Philosophical Transactions of the Royal Society A, 359, 1173-1185.
http://dx.doi.org/10.1098/rsta.2001.0824
[32] Trayanova, N., Li, W., Eason, J. and Kohl, P. (2004) Effect of stretch-activated channels on defibrillation efficacy. Heart Rhythm, 1, 67-77.
http://dx.doi.org/10.1016/j.hrthm.2004.01.002
[33] Kohl, P., Hunter, P. and Noble, D. (1999) Stretch-induced changes in heart rate and rhythm: Clinical observations, experiments and mathematical models. Progress in Biophysics and Molecular Biology, 71, 91-138.
http://dx.doi.org/10.1016/S0079-6107(98)00038-8
[34] Zabel, M., Koller, B.S., Sachs, F. and Franz, M.R. (1996) Stretch-induced voltage changes in the isolated beating heart: importance of the timing of stretch and implications for stretch-activated ion channels. Cardiovascular Research, 32, 120-130.
[35] Kamkin, A., Kiseleva, I. and Isenberg, G. (2000) Stretchactivated currents in ventricular myocytes: Amplitude and arrhythmogenic effects increase with hypertrophy. Cardiovascular Research, 48, 409-420.
http://dx.doi.org/10.1016/S0008-6363(00)00208-X
[36] Marsden, J.E. and Hughes, T.J.R. (1994) Mathematical foundations of elasticity. Dover Publications, New York.
[37] Holzapfel, G.A. (2000) Nonlinear solid mechanics: A continuum approach for engineering. John Wiley & Sons Ltd., Chichester.
[38] Pathmanathan, P. and Whiteley, J.P. (2009) A numerical method for cardiac mechanoelectric simulations. Annals of Biomedical Engineering, 37, 860-873.
http://dx.doi.org/10.1007/s10439-009-9663-8
[39] Costa, K.D., Holmes, J.W. and Mcculloch, A.D. (2001) Modelling cardiac mechanical properties in three dimensions. Philosophical Transactions of the Royal Society A, 359, 1233-1250. http://dx.doi.org/10.1098/rsta.2001.0828
[40] Hunter, P.J., Nash, M.P. and Sands, G.B. (1997) Computational mechanics of the heart. In: Panfilov, A.V. and Holden, A.V., Eds., Computational Biology of the Heart. Wiley, West Sussex, 345-407.
[41] Niederer, S.A. and Smith, N.P. (2008) An improved numerical method for strong coupling of excitation and contraction models in the heart. Progress in Biophysics and Molecular Biology, 96, 90-111.
http://dx.doi.org/10.1016/j.pbiomolbio.2007.08.001
[42] Whiteley, J.P., Bishop, M.J. and Gavaghan, D.J. (2007) Soft tissue modelling of cardiac fibres for use in coupled mechano-electric simulations. Bulletin of Mathematical Biology, 69, 2199-2225.
http://dx.doi.org/10.1007/s11538-007-9213-1
[43] Bonet, J. and Wood, R.D. (2008) Nonlinear continuum mechanics for finite element analysis. 2nd Edition, Cambridge University Press, Cambridge.
http://dx.doi.org/10.1017/CBO9780511755446
[44] Le Tallec, P. (1994) Numerical methods for nonlinear three-dimensional elasticity. In: Lions, J.L. and Ciarlet, P.G., Eds., Handbook of Numerical Analysis; Vol.3, Techniques of Scientific Computing (part 1); Numerical Methods for Solids (part 1); Solution of Equations in R(n) (part 2), North-Holland, London.
[45] Keldermann, R.H., Nash, M.P. and Panfilov, A.V (2009) Modeling cardiac mechano-electrical feedback using reaction-diffusion-mechanics systems. Physica D: Nonlinear Phenomena, 238, 1000-1007.
http://dx.doi.org/10.1016/j.physd.2008.08.017
[46] Auricchio, F., Beirao da Veiga, L., Lovadina, C. and Reali, A. (2010) The importance of the exact satisfaction of the incompressibility constraint in nonlinear elasticity: Mixed FEMs versus NURBS-based approximations. Computer Methods in Applied Mechanics and Engineering, 199, 314-323.
http://dx.doi.org/10.1016/j.cma.2008.06.004
[47] Braess, D. and Ming, P. (2005) A finite element method for nearly incompressible elasticity problems. Math Comp, 74, 25-52.
http://dx.doi.org/10.1090/S0025-5718-04-01662-X
[48] Braess, D. (2007) Finite elements: Theory, fast solvers, and applications in solid mechanics. 3rd Edition, Cambridge University Press, Cambridge.
http://dx.doi.org/10.1017/CBO9780511618635
[49] Brenner, S.C. and Scott, R. (2010) The mathematical theory of finite element methods. 3rd Edition, Springer, New York.
[50] Seemann, G., Keller, D.U.J., Weiss, D.L. and Dossel, O. (2006) Modeling human ventricular geometry and fiber orientation based on diffusion tensor MRI. Computers in Cardiology, 33, 801-804.
[51] Legrice, I.J., Hunter, P.J. and Smaill, B.H. (1997) Laminar structure of the heart: A mathematical model. The American Journal of Physiology, 272, H2466-H2476.
[52] Lilli, A., Baratto, M.T., Meglio, J.D., Chioccioli, M., Magnacca, M., Talini, E., Canale, M.L., Poddighe, R., Comella, A. and Casolo, G. (2013) Left ventricular rotation and twist assessed by four-dimensional speckle tracking echocardiography in healthy subjects and pathological remodeling: A single center experience. Echocardiography, 30, 171-179.
http://dx.doi.org/10.1111/echo.12026
[53] Lorenz, C.H., Pastorek, J.S. and Bundy, J.M. (2000) Delineation of normal human left ventricular twist throughout systole by tagged cine magnetic resonance imaging. Journal of Cardiovascular Magnetic Resonance, 2, 97-108. http://dx.doi.org/10.3109/10976640009148678
[54] Tseng, W-Y.I., Reese, T.G., Weisskoff, R.M., Brady, T.J. and Wedeen, V.J. (2000) Myocardial fiber shortening in humans: Initial results of MR imaging. Radiology, 216, 128-139. http://dx.doi.org/10.1148/radiology.216.1.r00jn39128
[55] MacGowan, G.A., Shapiro, E.P., Azhari, H., Siu, C.O., Hees, P.S., Hutchins, G.M., Weiss, J.L. and Rademakers, F.E. (1997) Noninvasive measurement of shortening in the fiber and cross-fiber directions in the normal human left ventricle and in idiopathic dilated cardiomyopathy. Circulation, 96, 535-541.
http://dx.doi.org/10.1161/01.CIR.96.2.535
[56] Coppola, B.A. and Omens, J.H. (2008) Role of tissue structure on ventricular wall mechanics. MCB Molecular and Cellular Biomechanics, 5, 183-196.
[57] Cheng, A., Nguyen, T.C., Malinowski, M., Daughters, G.T., Miller, D.C. and Ingels Jr., N.B. (2008) Heterogeneity of left ventricular wall thickening mechanisms. Circulation, 118, 713-721.
http://dx.doi.org/10.1161/CIRCULATIONAHA.107.744623
[58] Bogaert, J. and Rademakers, F.E. (2001) Regional nonuniformity of normal adult human left ventricle. American Journal of Physiology. Heart and Circulatory Physiology, 280, H610-H620.
[59] Guccione, J.M., McCulloch, A.D. and Waldman, L.K. (1991) Passive material properties of intact ventricular myocardium determined from a cylindrical model. Journal of Biomechanical Engineering, 113, 42-55.
http://dx.doi.org/10.1115/1.2894084
[60] Land, S., Niederer, S.A. and Smith, N.P. (2012) Efficient computational methods for strongly coupled cardiac electromechanics. IEEE Transactions on Biomedical Engineering, 59, 1219-1228.
http://dx.doi.org/10.1109/TBME.2011.2112359
[61] Colli Franzone, P., Pavarino, L.F. and Taccardi, B. (2005) Simulating patterns of excitation, repolarization and action potential duration with cardiac bidomain and monodomain models. Mathematical Biosciences, 197, 35-66.
http://dx.doi.org/10.1016/j.mbs.2005.04.003
[62] Potse, M., Dubé, B., Richer, J., Vinet, A. and Gulrajani, R.M. (2006) A comparison of monodomain and bidomain reaction-diffusion models for action potential propagation in the human heart. IEEE Transactions on Biomedical Engineering, 53, 2425-2435.
http://dx.doi.org/10.1109/TBME.2006.880875
[63] Keener, J. and Sneyd, J. (2008) Mathematical physiology: II: Systems physiology. 2nd Edition, Springer, New York.
[64] Nash, M.P. and Panfilov, A.V. (2004) Electromechanical model of excitable tissue to study reentrant cardiac arrhythmias. Progress in Biophysics and Molecular Biology, 85, 501-522.
http://dx.doi.org/10.1016/j.pbiomolbio.2004.01.016
[65] Taggart, P., Sutton, P.M., Opthof, T., Coronel, R., Trimlett, R., Pugsley, W. and Kallis, P. (2000) Inhomogeneous transmural conduction during early ischaemia in patients with coronary artery disease. Journal of Molecular and Cellular Cardiology, 32, 621-630.
http://dx.doi.org/10.1006/jmcc.2000.1105
[66] Plonsey, R. and Barr, R.C. (2007) Bioelectricity: A quantitative approach. 3rd Edition, Springer, New York.
[67] Drouin, E., Charpentier, F., Gauthier, C., Laurent, K. and Le Marec, H. (1995) Electrophysiologic characteristics of cells spanning the left ventricular wall of human heart: Evidence for presence of M cells. Journal of the American College of Cardiology, 26, 185-192.
http://dx.doi.org/10.1016/0735-1097(95)00167-X
[68] Keller, D.U.J., Kalayciyan, R., Dossel, O. and Seemann, G. (2009) Fast creation of endocardial stimulation profiles for the realistic simulation of body surface ECGs. Proceedings of the World Congress on Medical Physics and Biomedical Engineering IFMBE, Munich, 7-12 September 2009, 145-148.
[69] Sundnes, J., Lines, G.T. and Tveito, A. (2005) An operator splitting method for solving the bidomain equations coupled to a volume conductor model for the torso. Mathematical Biosciences, 194, 233-248.
http://dx.doi.org/10.1016/j.mbs.2005.01.001
[70] Burnett, D.S. (1987) Finite element analysis: From concepts to applications. Addison Wesley, Massachusetts.
[71] Ern, A. and Guermond, J.L. (2010) Theory and practice of finite elements. Springer, New York.
[72] Rush, S. and Larsen, H. (1978) A practical algorithm for solving dynamic membrane equations. IEEE Transactions on Biomedical Engineering, 25, 389-392.
http://dx.doi.org/10.1109/TBME.1978.326270
[73] Cohen, S. and Hindmarsh, A.C. (1996) CVODE, A stiff/ nonstiff ode solver in C. In: Holmes, L.M. Ed., Computers in Physics, American Institute of Physics Inc, New York, 138-143
[74] Hindmarsh, A.C., Brown, P.N., Grant, K.E., Lee, S.L., Serban, R., Shumaker, D.E. and Woodward, C.S. (2005) SUNDIALS: Suite of nonlinear and differential/algebraic equation solvers. ACM Transactions on Mathematical Software, 31, 363-396.
http://dx.doi.org/10.1145/1089014.1089020
[75] Logg, A., Mardal, K.A. and Wells, G. (2012) Automated solution of differential equations by the finite element method: The FEniCS book. Springer, New York.
http://dx.doi.org/10.1007/978-3-642-23099-8
[76] Chamberland, E., Fortin, A. and Fortin, M. (2010) Comparison of the performance of some finite element discretizations for large deformation elasticity problems. Computers & Structures, 88, 664-673.
http://dx.doi.org/10.1016/j.compstruc.2010.02.007
[77] Haga, J.B., Osnes, H. and Langtangen, H.P. (2012) On the causes of pressure oscillations in low-permeable and low-compressible porous media. International Journal for Numerical and Analytical Methods in Geomechanics, 36, 1507-1522. http://dx.doi.org/10.1002/nag.1062
[78] Hughes, T.J.R. (2000) The finite element method: Linear static and dynamic finite element analysis. Dover Publications, Dover.
[79] McIntosh, M.A., Cobbe, S.M. and Smith, G.L. (2000) Heterogeneous changes in action potential and intracellular Ca2+ in left ventricular myocyte sub-types from rabbits with heart failure. Cardiovascular Research, 45, 397-409.
http://dx.doi.org/10.1016/S0008-6363(99)00360-0
[80] Woodworth, R.S. (1902) Maximal contraction, ‘staircase’ contraction, refractory period, and compensatory pause, of the heart. American Journal of Physiology, 8, 213-249.
[81] Mulieri, L.A., Hasenfuss, G., Leavitt, B., Allen, P.D. and Alpert, N.R. (1992) Altered myocardial force-frequency relation in human heart failure. Circulation, 85, 1743-1750.
http://dx.doi.org/10.1161/01.CIR.85.5.1743
[82] Lakatta, E.G. (2004) Beyond Bowditch: The convergence of cardiac chronotropy and inotropy. Cell Calcium, 35, 629-642. http://dx.doi.org/10.1016/j.ceca.2004.01.017
[83] Boland, J. and Troquet, J. (1980) Intracellular action potential changes induced in both ventricles of the rat by an acute right ventricular pressure overload. Cardiovascular Research, 14, 735-740.
http://dx.doi.org/10.1093/cvr/14.12.735
[84] Franz, M.R., Cima, R., Wang, D., Profitt, D. and Kurz, R. (19920 Electrophysiological effects of myocardial stretch and mechanical determinants of stretch-activated arrhythmias. Circulation, 86, 968-978.
http://dx.doi.org/10.1161/01.CIR.86.3.968
[85] Calkins, H., El-Atassi, R., Kalbfleisch, S., Langberg, J. and Morady, F. (1992) Effects of an acute increase in atrial pressure on atrial refractoriness in humans. Pacing and Clinical Electrophysiology, 15, 1674-1680.
http://dx.doi.org/10.1111/j.1540-8159.1992.tb02954.x
[86] Alvarez, B.V., Pérez, N.G., Ennis, I.L., Camilión de Hurtado, M.C. and Cingolani, H.E. (1999) Mechanisms underlying the increase in force and Ca2+ transient that follow stretch of cardiac muscle: A possible explanation of the Anrep effect. Circulation Research, 85, 716-722.
http://dx.doi.org/10.1161/01.RES.85.8.716
[87] Baartscheer, A., Schumacher, C.A., van Borren M.M.G.J, Belterman, C.N.W, Coronel, R. and Fiolet, J.W.T. (2003) Increased Na+/H+-exchange activity is the cause of increased [Na+]i and underlies disturbed calcium handling in the rabbit pressure and volume overload heart failure model. Cardiovascular Research, 57, 1015-1024.
http://dx.doi.org/10.1016/S0008-6363(02)00809-X
[88] Calaghan, S.C., Belus, A. and White, E. (2003) Do stretchinduced changes in intracellular calcium modify the electrical activity of cardiac muscle? Progress in Biophysics and Molecular Biology, 82, 81-95.
http://dx.doi.org/10.1016/S0079-6107(03)00007-5
[89] Calaghan, S.C. and White, E. (1999) The role of calcium in the response of cardiac muscle to stretch. Progress in Biophysics and Molecular Biology, 71, 59-90.
http://dx.doi.org/10.1016/S0079-6107(98)00037-6
[90] Barcenas-Ruiz, L., Beuckelmann, D.J. and Wier, W.G. (1987) Sodium-calcium exchange in heart: Membrane currents and changes in [Ca2+]i. Science, 238, 1720-1722.
http://dx.doi.org/10.1126/science.3686010
[91] Hall, J.E. and Guyton, A.C. (2010) Textbook of medical physiology. 12th Edition, Saunders, Philadelphia.
[92] Rhoades, R. and Bell, D.R. (2013) Medical physiology: principles for clinical medicine. 4th Edition, Wolters Kluwer Health/Lippincott Williams & Wilkins, Philadelphia.
[93] DiMino, T.L., Ivanov, A., Burke, J.F. and Kowey, P.R. (2006) Electrocardiography. In: Rosendorff, C., Ed., Essential Cardiology: Principles and Practice, Humana Press, Clifton, 117-138.
http://dx.doi.org/10.1007/978-1-59259-918-9_8
[94] Klabunde, R.E. (2012) Cardiovascular physiology concepts. 2nd Edition, Lippincott Williams & Wilkins/Wolters Kluwer, Philadelphia.
[95] Bett, G.C. and Sachs, F. (1997) Cardiac mechanosensitivity and stretch-activated ion channels. Trends in Cardiovascular Medicine, 7, 4-8.
http://dx.doi.org/10.1016/S1050-1738(96)00119-3
[96] Sengupta, P.P., Tajik, A.J., Chandrasekaran, K. and Khandheria, B.K. (2008) Twist mechanics of the left ventricle: Principles and application. JACC: Cardiovascular Imaging, 1, 366-376. http://dx.doi.org/10.1016/j.jcmg.2008.02.006
[97] Sengupta, P.P., Khandheria, B.K. and Narula, J. (2008) Twist and untwist mechanics of the left ventricle. Heart Failure Clinics, 4, 315-324.
http://dx.doi.org/10.1016/j.hfc.2008.03.001
[98] Hodt, A., Stugaard, M., Hisdal, J., Stranden, E., Atar, D. and Steine, K. (2012) Regional LV deformation in healthy individuals during isovolumetric contraction and ejection phases assessed by 2D speckle tracking echocardiography. Clinical Physiology and Functional Imaging, 32, 372-379.
http://dx.doi.org/10.1111/j.1475-097X.2012.01139.x
[99] Lionel, H.O. (2006) Ventricular Function. In: Rosendorff, C., Ed., Essential Cardiology: Principles and Practice, Human Press, New Jersey, 37-54.
[100] Wei, Q., Liu, F., Appleton, B., Xia, L., Liu, N., Wilson, S., Riley, R., Strugnel, W., Slaughter, R., Denman, R. and Crozier, S. (2006) Effect of cardiac motion on body surface electrocardiographic potentials: An MRI-based simulation study. Physics in Medicine and Biology, 51, 3405-3418. http://dx.doi.org/10.1088/0031-9155/51/14/009
[101] Xia, L., Huo, M., Wei, Q., Liu, F. and Crozier, S. (2005) Analysis of cardiac ventricular wall motion based on a three-dimensional electromechanical biventricular model. Physics in Medicine and Biology, 50, 1901-1917.
http://dx.doi.org/10.1088/0031-9155/50/8/018
[102] Smith, N.P., Buist, M.L. and Pullan, A.J. (2003) Altered T wave dynamics in a contracting cardiac model. Journal of Cardiovascular Electrophysiology, 14, S203-S209.
http://dx.doi.org/10.1046/j.1540.8167.90312.x
[103] Mao, H.D., Wang, L.W., Wong, C.L., Liu, H.F. and Shi, P.C. (2011) A coupled heart-torso framework for cardiac electrocardiographic simulation. Computing in Cardiology, 38, 225-228.
[104] Horner, S.M., Dick, D.J., Murphy, C.F. and Lab, M.J. (1996) Cycle length dependence of the electrophysiological effects of increased load on the myocardium. Circulation, 94, 1131-1136.
http://dx.doi.org/10.1161/01.CIR.94.5.1131
[105] Sung, D., Mills, R.W., Schettler, J., Narayan, S.M., Omens, J.H. and McCulloch, A.D. (2003) Ventricular filling slows epicardial conduction and increases action potential duration in an optical mapping study of the isolated rabbit heart. Journal of Cardiovascular Electrophysiology, 14, 739-749.
http://dx.doi.org/10.1046/j.1540-8167.2003.03072.x
[106] Kohl, P., Camelliti, P., Burton, F.L. and Smith, G.L. (2005) Electrical coupling of fibroblasts and myocytes: Relevance for cardiac propagation. Journal of Electrocardiology, 38, 45-50.
http://dx.doi.org/10.1016/j.jelectrocard.2005.06.096
[107] Thompson, S.A., Copeland, C.R., Reich, D.H. and Tung, L. (2011) Mechanical coupling between myofibroblasts and cardiomyocytes slows electric conduction in fibrotic cell monolayers. Circulation, 123, 2083-2093.
http://dx.doi.org/10.1161/CIRCULATIONAHA.110.015057

  
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