© 1996 American Heart Association, Inc.
Articles |
Anisotropic Activation Spread in Heart Cell Monolayers Assessed by High-Resolution Optical Mapping
Role of Tissue Discontinuities
the Department of Physiology (V.G.F., A.G.K.), University of Berne (Switzerland), and the Department of Pathology (B.J.D., J.E.S.), Washington University, St. Louis, Mo.
Correspondence to V.G. Fast, PhD, or A.G. Kleber, MD, Department of Physiology, University of Berne, Buhlplatz 5, CH-3012, Berne, Switzerland. E-mail fast@pyl.unibe.ch. E-mail kleber@pyl.unibe.ch.
The role of tissue discontinuities in anisotropic impulse propagation was assessed in two-dimensional anisotropic monolayers of neonatal rat myocytes cultured on a growth-directing substrate of collagen. Activation spread and distribution of maximal upstroke rate of rise (Vmax) of the action potential were measured with an optical system using a voltage-sensitive fluorescent dye (RH-327) and a 10x10 photodiode array with a spatial resolution ranging from 7 to 15 µm. Activation maps were compared with the cellular architecture and the distribution of gap junctions obtained from immunostaining the gap junction protein connexin43 (Cx43). Four types of structures were studied: (1) dense cell cultures, (2) cultures with anisotropic intercellular clefts of variable size, (3) discontinuities created by inclusion of nonmyocyte cells, and (4) discontinuities resulting from nonuniform expression of gap junctions. In dense monolayers, activation spread was continuous with microinhomogeneities in both longitudinal and transverse directions. The average cell dimensions in such monolayers were smaller than in adult canine myocardium. However, the degree of cellular anisotropy (length-to-width ratio of 5.3±1.4) and connectivity were similar. The presence of small intercellular clefts (less than one cell in length) did not disturb the general pattern of transverse or longitudinal activation spread, but it was associated with wave front microcollisions during transverse propagation and a concomitant increase of Vmax beyond the cleft. Long intercellular clefts caused discontinuous transverse propagation. Conduction velocity and Vmax decreased significantly at narrow isthmuses formed by closely apposed clefts, rendering such sites susceptible for conduction block. In contrast, Vmax increased when the wave front faced the borders of the clefts. Nonmyocyte cells were electrically connected to myocytes and served as sinks for electrotonic currents, thereby producing localized conduction slowing and a decrease in Vmax. Localized inhomogeneity in Cx43 distribution correlated accurately with circumscribed conduction block and changes in Vmax. Our results provide direct experimental evidence that the cellular structure and gap junction distribution correlate with action potential propagation and distribution of Vmax. We suggest that in tissue with a nonuniform anisotropy, connective tissue separating fiber bundles or sites of inhomogeneous connexin distribution may represent predilective sites for block in transverse direction.
Key Words: cell culture • ventricular myocytes • anisotropy • collagen • voltage-sensitive dyes
This article has been cited by other articles:
 |
|
 |
|
  P. Menasche Stem Cell Therapy for Heart Failure: Are Arrhythmias a Real Safety Concern? Circulation, May 26, 2009; 119(20): 2735 - 2740. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. A. Pijnappels, M. J. Schalij, A. A. Ramkisoensing, J. van Tuyn, A. A.F. de Vries, A. van der Laarse, D. L. Ypey, and D. E. Atsma Forced Alignment of Mesenchymal Stem Cells Undergoing Cardiomyogenic Differentiation Affects Functional Integration With Cardiomyocyte Cultures Circ. Res., July 18, 2008; 103(2): 167 - 176. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 V. Jacquemet and C. S. Henriquez Loading effect of fibroblast-myocyte coupling on resting potential, impulse propagation, and repolarization: insights from a microstructure model Am J Physiol Heart Circ Physiol, May 1, 2008; 294(5): H2040 - H2052. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Yankelson, Y. Feld, T. Bressler-Stramer, I. Itzhaki, I. Huber, A. Gepstein, D. Aronson, S. Marom, and L. Gepstein Cell Therapy for Modification of the Myocardial Electrophysiological Substrate Circulation, February 12, 2008; 117(6): 720 - 731. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. L. Hubbard, W. Ying, and C. S. Henriquez Effect of gap junction distribution on impulse propagation in a monolayer of myocytes: a model study Europace, November 1, 2007; 9(suppl_6): vi20 - vi28. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Beauchamp, K. A. Yamada, A. J. Baertschi, K. Green, E. M. Kanter, J. E. Saffitz, and A. G. Kleber Relative Contributions of Connexins 40 and 43 to Atrial Impulse Propagation in Synthetic Strands of Neonatal and Fetal Murine Cardiomyocytes Circ. Res., November 24, 2006; 99(11): 1216 - 1224. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. E. Pollard and R. C. Barr Cardiac microimpedance measurement in two-dimensional models using multisite interstitial stimulation Am J Physiol Heart Circ Physiol, May 1, 2006; 290(5): H1976 - H1987. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. L.M.A. Beeres, D. E. Atsma, A. van der Laarse, D. A. Pijnappels, J. van Tuyn, W. E. Fibbe, A. A.F. de Vries, D. L. Ypey, E. E. van der Wall, and M. J. Schalij Human Adult Bone Marrow Mesenchymal Stem Cells Repair Experimental Conduction Block in Rat Cardiomyocyte Cultures J. Am. Coll. Cardiol., November 15, 2005; 46(10): 1943 - 1952. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. G. Kleber The Shape of the Electrical Action-Potential Upstroke: A New Aspect From Optical Measurements on the Surface of the Heart Circ. Res., August 5, 2005; 97(3): 204 - 206. [Full Text] [PDF]
|
|
|
|
|
|
P. Swietach and R. D. Vaughan-Jones Novel method for measuring junctional proton permeation in isolated ventricular myocyte cell pairs Am J Physiol Heart Circ Physiol, November 1, 2004; 287(5): H2352 - H2363. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Beauchamp, C. Choby, T. Desplantez, K. de Peyer, K. Green, K. A. Yamada, R. Weingart, J. E. Saffitz, and A. G. Kleber Electrical Propagation in Synthetic Ventricular Myocyte Strands From Germline Connexin43 Knockout Mice Circ. Res., July 23, 2004; 95(2): 170 - 178. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Rohr Role of gap junctions in the propagation of the cardiac action potential Cardiovasc Res, May 1, 2004; 62(2): 309 - 322. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. G. KLEBER and Y. RUDY Basic Mechanisms of Cardiac Impulse Propagation and Associated Arrhythmias Physiol Rev, April 1, 2004; 84(2): 431 - 488. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Gepstein, Y. Feld, and L. Yankelson Somatic gene and cell therapy strategies for the treatment of cardiac arrhythmias Am J Physiol Heart Circ Physiol, March 1, 2004; 286(3): H815 - H822. [Full Text] [PDF]
|
|
|
|
|
|
A. G. Kleber Cell-to-Cell Coupling Between Host and Donor Cells in the In Situ Myocardium Circ. Res., June 13, 2003; 92(11): 1176 - 1178. [Full Text] [PDF]
|
|
|
|
|
|
S. P. Thomas, J. P. Kucera, L. Bircher-Lehmann, Y. Rudy, J. E. Saffitz, and A. G. Kleber Impulse Propagation in Synthetic Strands of Neonatal Cardiac Myocytes With Genetically Reduced Levels of Connexin43 Circ. Res., June 13, 2003; 92(11): 1209 - 1216. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Rubart, K. B.S. Pasumarthi, H. Nakajima, M. H. Soonpaa, H. O. Nakajima, and L. J. Field Physiological Coupling of Donor and Host Cardiomyocytes After Cellular Transplantation Circ. Res., June 13, 2003; 92(11): 1217 - 1224. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. Bursac, K.K. Parker, S. Iravanian, and L. Tung Cardiomyocyte Cultures With Controlled Macroscopic Anisotropy: A Model for Functional Electrophysiological Studies of Cardiac Muscle Circ. Res., December 13, 2002; 91 (12): e45 - e54. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. Kehat, A. Gepstein, A. Spira, J. Itskovitz-Eldor, and L. Gepstein High-Resolution Electrophysiological Assessment of Human Embryonic Stem Cell-Derived Cardiomyocytes: A Novel In Vitro Model for the Study of Conduction Circ. Res., October 18, 2002; 91(8): 659 - 661. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D Sanchez-Quintana, R H Anderson, J A Cabrera, V Climent, R Martin, J Farre, and S Y Ho The terminal crest: morphological features relevant to electrophysiology Heart, October 1, 2002; 88(4): 406 - 411. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. C. Pimentel, K. A. Yamada, A. G. Kleber, and J. E. Saffitz Autocrine Regulation of Myocyte Cx43 Expression by VEGF Circ. Res., April 5, 2002; 90(6): 671 - 677. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Feld, M. Melamed-Frank, I. Kehat, D. Tal, S. Marom, and L. Gepstein Electrophysiological Modulation of Cardiomyocytic Tissue by Transfected Fibroblasts Expressing Potassium Channels: A Novel Strategy to Manipulate Excitability Circulation, January 29, 2002; 105(4): 522 - 529. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. A.B. van Veen, H. V.M. van Rijen, and T. Opthof Cardiac gap junction channels: modulation of expression and channel properties Cardiovasc Res, August 1, 2001; 51(2): 217 - 229. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Becker, A. Bauer, S. Metz, R. Kinscherf, J. C. Senges, K. D. Schreiner, F. Voss, W. Kuebler, and W. Schoels Intercaval Block in Normal Canine Hearts : Role of the Terminal Crest Circulation, May 22, 2001; 103(20): 2521 - 2526. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Arutunyan, D. R. Webster, L. M. Swift, and N. Sarvazyan Localized injury in cardiomyocyte network: a new experimental model of ischemia-reperfusion arrhythmias Am J Physiol Heart Circ Physiol, April 1, 2001; 280(4): H1905 - H1915. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Tung and A. G. Kleber Virtual sources associated with linear and curved strands of cardiac cells Am J Physiol Heart Circ Physiol, October 1, 2000; 279(4): H1579 - H1590. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. P. Thomas, L. Bircher-Lehmann, S. A. Thomas, J. Zhuang, J. E. Saffitz, and A. G. Kleber Synthetic Strands of Neonatal Mouse Cardiac Myocytes : Structural and Electrophysiological Properties Circ. Res., September 15, 2000; 87(6): 467 - 473. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Zhuang, K. A. Yamada, J. E. Saffitz, and A. G. Kleber Pulsatile Stretch Remodels Cell-to-Cell Communication in Cultured Myocytes Circ. Res., August 18, 2000; 87(4): 316 - 322. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. G. Fast, S. Rohr, and R. E. Ideker Nonlinear changes of transmembrane potential caused by defibrillation shocks in strands of cultured myocytes Am J Physiol Heart Circ Physiol, March 1, 2000; 278(3): H688 - H697. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. S. Spach, J. F. Heidlage, P. C. Dolber, and R. C. Barr Electrophysiological Effects of Remodeling Cardiac Gap Junctions and Cell Size : Experimental and Model Studies of Normal Cardiac Growth Circ. Res., February 18, 2000; 86(3): 302 - 311. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. Bursac, M. Papadaki, R. J. Cohen, F. J. Schoen, S. R. Eisenberg, R. Carrier, G. Vunjak-Novakovic, and L. E. Freed Cardiac muscle tissue engineering: toward an in vitro model for electrophysiological studies Am J Physiol Heart Circ Physiol, August 1, 1999; 277(2): H433 - H444. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. S. Spach, J. F. Heidlage, P. C. Dolber, and R. C. Barr Extracellular Discontinuities in Cardiac Muscle : Evidence for Capillary Effects on the Action Potential Foot Circ. Res., November 30, 1998; 83(11): 1144 - 1164. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Rohr, J. P. Kucera, and A. G. Kleber Slow Conduction in Cardiac Tissue, I : Effects of a Reduction of Excitability Versus a Reduction of Electrical Coupling on Microconduction Circ. Res., October 19, 1998; 83(8): 781 - 794. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. S. Peters and A. L. Wit Myocardial Architecture and Ventricular Arrhythmogenesis Circulation, May 5, 1998; 97(17): 1746 - 1754. [Full Text] [PDF]
|
|
|
|
|
|
V. G. Fast, S. Rohr, A. M. Gillis, and A. G. Kleber Activation of Cardiac Tissue by Extracellular Electrical Shocks : Formation of `Secondary Sources' at Intercellular Clefts in Monolayers of Cultured Myocytes Circ. Res., February 23, 1998; 82(3): 375 - 385. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. M. Shaw and Y. Rudy Ionic Mechanisms of Propagation in Cardiac Tissue : Roles of the Sodium and L-type Calcium Currents During Reduced Excitability and Decreased Gap Junction Coupling Circ. Res., November 19, 1997; 81(5): 727 - 741. [Abstract] [Full Text]
|
|
|
|
|
|
A. M. Gillis, V. G. Fast, S. Rohr, and A. G. Kleber Spatial Changes in Transmembrane Potential During Extracellular Electrical Shocks in Cultured Monolayers of Neonatal Rat Ventricular Myocytes Circ. Res., October 1, 1996; 79(4): 676 - 690. [Abstract] [Full Text]
|
|
|
|
|
|
D. Vaidya, H. S. Tamaddon, C. W. Lo, S. M. Taffet, M. Delmar, G. E. Morley, and J. Jalife Null Mutation of Connexin43 Causes Slow Propagation of Ventricular Activation in the Late Stages of Mouse Embryonic Development Circ. Res., June 8, 2001; 88(11): 1196 - 1202. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. E. Cascio, H. Yang, T. A. Johnson, B. J. Muller-Borer, and J. J. Lemasters Electrical Properties and Conduction in Reperfused Papillary Muscle Circ. Res., October 26, 2001; 89(9): 807 - 814. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. C. Pimentel, K. A. Yamada, A. G. Kleber, and J. E. Saffitz Autocrine Regulation of Myocyte Cx43 Expression by VEGF Circ. Res., April 5, 2002; 90(6): 671 - 677. [Abstract] [Full Text] [PDF]
|
|