|
|
||||||||
1Department of Cardiovascular and Thoracic Surgery, Stanford University School of Medicine, Stanford; 3Laboratory of Cardiovascular Physiology and Biophysics, Research Institute of The Palo Alto Medical Foundation, Palo Alto, California; and 2Department of Biomedical Engineering, Texas A & M University, College Station, Texas
Submitted 7 February 2005 ; accepted in final form 26 April 2005
In an attempt to provide a better understanding of our finding that regions with contracting left ventricular myofibers need not develop a significant transmural systolic wall thickening gradient, the analytic approach of Costa et al. (Am J Physiol Heart Circ Physiol 276: H595H607, 1999) was applied to the four-dimensional dynamic data obtained 1 and 8 wk after surgical implantation of transmural radiopaque beads in the lateral equatorial left ventricular wall in seven ovine hearts. Quantitative histology of tissue blocks demonstrated that fiber angles varied linearly across the wall in this region from 37° in the subepicardium to +18° in the subendocardium. Sheet angles exhibited a pleated-sheet behavior, alternating sign from subepicardium to subendocardium. From end diastole (reference configuration) to end systole (deformed configuration), fiber strain was uniformly negative, sheet extension and sheet thickening were uniformly positive, and sheet-normal shear contributed to wall thickening at all wall depths. Subepicardial radial wall thickening increased significantly from week 1 to week 8, with significant increases in the contributions from subepicardial sheet extension and sheet-normal shear. At 1 and 8 wk, the contribution of sheet-normal shear to wall thickening was substantial at all transmural depths; the contribution of sheet extension to wall thickening was greatest in the subepicardium and least in the subendocardium, and the contribution of sheet thickening to wall thickening was greatest in the subendocardium and least in the subepicardium. A mechanistic model is proposed that provides a working hypothesis that a selective decrease in subepicardial intercellular matrix stiffness is responsible for elimination of the transmural wall thickening gradient 18 wk after marker implantation surgery.
wall thickening; myocardium; systolic function
This article has been cited by other articles:
![]() |
A. J. Pope, G. B. Sands, B. H. Smaill, and I. J. LeGrice Three-dimensional transmural organization of perimysial collagen in the heart Am J Physiol Heart Circ Physiol, September 1, 2008; 295(3): H1243 - H1252. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Cheng, T. C. Nguyen, M. Malinowski, G. T. Daughters, D. C. Miller, and N. B. Ingels Jr Heterogeneity of Left Ventricular Wall Thickening Mechanisms Circulation, August 12, 2008; 118(7): 713 - 721. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. H. Gilbert, A. P. Benson, P. Li, and A. V. Holden Regional localisation of left ventricular sheet structure: integration with current models of cardiac fibre, sheet and band structure Eur. J. Cardiothorac. Surg., August 1, 2007; 32(2): 231 - 249. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. C. Nguyen, A. Cheng, F. A. Tibayan, D. Liang, G. T. Daughters, N. B. Ingels Jr., and D. C. Miller Septal-lateral annnular cinching perturbs basal left ventricular transmural strains Eur. J. Cardiothorac. Surg., March 1, 2007; 31(3): 423 - 429. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. C. Nguyen, A. Cheng, F. Langer, F. Rodriguez, R. A. Oakes, A. Itoh, D. B. Ennis, D. Liang, G. T. Daughters, N. B. Ingels Jr, et al. Altered Myocardial Shear Strains Are Associated With Chronic Ischemic Mitral Regurgitation Ann. Thorac. Surg., January 1, 2007; 83(1): 47 - 54. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Cheng, T. C. Nguyen, M. Malinowski, D. Liang, G. T. Daughters, N. B. Ingels Jr, and D. C. Miller Effects of Undersized Mitral Annuloplasty on Regional Transmural Left Ventricular Wall Strains and Wall Thickening Mechanisms Circulation, July 4, 2006; 114(1_suppl): I-600 - I-609. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |