Abstract
Left ventricular outflow tract obstruction (LVOTO) is one of the defining features of hypertrophic cardiomyopathy (HCM) and one of the main determinants of prognosis. Although the importance of obstruction was recognized since the original description by Teare and Brock, its exact cause and methods for its relief are still being hotly debated. We believe that a rational approach to solving these issues depends on thorough understanding of the specific structure and functions of the left ventricular outflow tract (LVOT) in health and disease. There is now compelling evidence that the LVOT performs a series of vital sophisticated functions which are mediated by the design characteristics, structure, and biological properties of its component parts and that dysregulation of one or more of these functions results in obstruction and other abnormalities. We here review the integrated functions of the LVOT, its structural and functional relationships, with particular reference to its component parts (the major players) and their role in HCM. This knowledge is essential to evolve tailored restorative techniques for treating HCM.
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Maron, M. S., Olivotto, I., Zenovich, A. G., et al. (2006). Hypertrophic cardiomyopathy is predominantly a disease of left ventricular outflow tract obstruction. Circulation, 114, 2232–2239.
Maron, M. S., Olivotto, I., Betocchi, S., et al. (2003). Effect of left ventricular outflow tract obstruction on clinical outcome in hypertrophic cardiomyopathy. The New England journal of medicine, 348, 295–303.
Brock, R. (1959). Functional obstruction of the left ventricle (acquired aortic subvalvar stenosis). Guy’s Hospital Reports, 108, 126–143.
Brock, R. (1957). Functional obstruction of the left ventricle; acquired aortic subvalvar stenosis. Guy’s Hospital Reports, 106, 221–238.
Teare, D. (1958). Asymmetrical hypertrophy of the heart in young adults. British heart journal, 20, 1–8.
Yacoub, M. H., Kilner, P. J., Birks, E. J., & Misfeld, M. (1999). The aortic outflow and root: a tale of dynamism and crosstalk. Annals of Thoracic Surgery, 68, S37–S43.
Kilner, P. J., Yang, G. Z., Wilkes, A. J., Mohiaddin, R. H., Firmin, D. N., & Yacoub, M. H. (2000). Asymmetric redirection of flow through the heart. Nature, 404, 759–761.
Helderman, F., Segers, D., de Crom, R., et al. (2007). Effect of shear stress on vascular inflammation and plaque development. Current Opinion in Lipidology, 18, 527–533.
El-Hamamsy, I., & Yacoub, M. H. (2009). Cellular and molecular mechanisms of thoracic aortic aneurysms. Nature Reviews Cardiology, 6, 771–786.
Davies, J. E., Parker, K. H., Francis, D. P., Hughes, A. D., & Mayet, J. (2008). What is the role of the aorta in directing coronary blood flow? Heart, 94, 1545–1547.
Lie-Venema, H., van den Akker, N. M. S., Bax, N. A. M., et al. (2007). Origin, fate, and function of epicardium-derived cells (EPDCs) in normal and abnormal cardiac development. TheScientificWorldJOURNAL, 7, 1777–1798.
Olivotto, I., Cecchi, F., Poggesi, C., & Yacoub, M. H. (2009). Developmental origins of hypertrophic cardiomyopathy phenotypes: a unifying hypothesis. Nature Reviews Cardiology, 6, 317–321.
Bertho, E., & Gagnon, G. (1964). A comparative study in three dimension of the blood supply of the normal interventricular septum in human, canine, bovine, porcine, ovine and equine heart. Diseases of the chest, 46, 251–262.
Merrick, A. F., Yacoub, M. H., Ho, S. Y., & Anderson, R. H. (2000). Anatomy of the muscular subpulmonary infundibulum with regard to the Ross procedure. Annals of Thoracic Surgery, 69, 556–561.
Muresian, H. (2006). The Ross procedure: new insights into the surgical anatomy. Annals of Thoracic Surgery, 81, 495–501.
Sigwart, U. (1995). Non-surgical myocardial reduction for hypertrophic obstructive cardiomyopathy. Lancet, 346, 211–214.
Zimmerman, J. (1966). The functional and surgical anatomy of the heart. Annals of the Royal College of Surgeons of England, 39, 348–366.
Icardo, J. M. (1996). Developmental biology of the vertebrate heart. The Journal of experimental zoology, 275, 144–161.
Yang, G. Z., Merrifield, R., Masood, S., & Kilner, P. J. (2007). Flow and myocardial interaction: an imaging perspective. Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences, 362, 1329–1341.
Dagum, P., Green, G. R., Nistal, F. J., et al. (1999). Deformational dynamics of the aortic root: modes and physiologic determinants. Circulation, 100, II54–II62.
Lansac, E., Lim, H. S., Shomura, Y., et al. (2005). Aortic root dynamics are asymmetric. Journal of heart valve disease, 14, 400–407.
Lansac, E., Lim, H. S., Shomura, Y., et al. (2002). A four-dimensional study of the aortic root dynamics. European Journal of Cardio-Thoracic Surgery, 22, 497–503.
El-Hamamsy, I., Balachandran, K., Yacoub, M. H., et al. (2009). Endothelium-dependent regulation of the mechanical properties of aortic valve cusps. Journal of the American College of Cardiology, 53, 1448–1455.
Markl, M., Draney, M. T., Hope, M. D., et al. (2004). Time-resolved 3-dimensional velocity mapping in the thoracic aorta: visualization of 3-directional blood flow patterns in healthy volunteers and patients. Journal of computer assisted tomography, 28, 459–468.
Yacoub, M. H. (2005). Surgical versus alcohol septal ablation for hypertrophic obstructive cardiomyopathy: the pendulum swings. Circulation, 112, 450–452.
Binder, J., Ommen, S. R., Gersh, B. J., et al. (2006). Echocardiography-guided genetic testing in hypertrophic cardiomyopathy: septal morphological features predict the presence of myofilament mutations. Mayo Clinic Proceedings, 81, 459–467.
Bujak, M., & Frangogiannis, N. G. (2007). The role of TGF-{beta} signaling in myocardial infarction and cardiac remodeling. Cardiovascular Research, 74, 184–195.
He, S., Hopmeyer, J., Lefebvre, X. P., Schwammenthal, E., Yoganathan, A. P., & Levine, R. A. (1997). Importance of leaflet elongation in causing systolic anterior motion of the mitral valve. Journal of heart valve disease, 6, 149–159.
Klues, H. G., Proschan, M. A., Dollar, A. L., Spirito, P., Roberts, W. C., & Maron, B. J. (1993). Echocardiographic assessment of mitral valve size in obstructive hypertrophic cardiomyopathy. Anatomic validation from mitral valve specimen. Circulation, 88, 548–555.
Klues, H. G., Maron, B. J., Dollar, A. L., & Roberts, W. C. (1992). Diversity of structural mitral valve alterations in hypertrophic cardiomyopathy. Circulation, 85, 1651–1660.
Levine, R. A., Vlahakes, G. J., Lefebvre, X., et al. (1995). Papillary muscle displacement causes systolic anterior motion of the mitral valve. Experimental validation and insights into the mechanism of subaortic obstruction. Circulation, 91, 1189–1195.
Klues, H. G., Roberts, W. C., & Maron, B. J. (1991). Anomalous insertion of papillary muscle directly into anterior mitral leaflet in hypertrophic cardiomyopathy. Significance in producing left ventricular outflow obstruction. Circulation, 84, 1188–1197.
Sherrid, M. V., Chaudhry, F. A., & Swistel, D. G. (2003). Obstructive hypertrophic cardiomyopathy: echocardiography, pathophysiology, and the continuing evolution of surgery for obstruction. Annals of Thoracic Surgery, 75, 620–632.
Klues, H. G., Roberts, W. C., & Maron, B. J. (1993). Morphological determinants of echocardiographic patterns of mitral valve systolic anterior motion in obstructive hypertrophic cardiomyopathy. Circulation, 87, 1570–1579.
Cecchi, F., Olivotto, I., Nistri, S., Antoniucci, D., & Yacoub, M. H. (2006). Midventricular obstruction and clinical decision-making in obstructive hypertrophic cardiomyopathy. Herz, 31, 871–876.
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The authors would like to acknowledge Ms. Sherine George for producing the illustrations.
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Magdi H. Yacoub and Ismail El-Hamamsy contributed equally to this manuscript.
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Yacoub, M.H., El-Hamamsy, I., Said, K. et al. The Left Ventricular Outflow in Hypertrophic Cardiomyopathy: From Structure to Function. J. of Cardiovasc. Trans. Res. 2, 510–517 (2009). https://doi.org/10.1007/s12265-009-9153-2
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DOI: https://doi.org/10.1007/s12265-009-9153-2