CONTROVERSIES IN FELINE CARDIOMYOPATHY: FELINE LEFT VENTRICULAR NONCOMPACTION - REAL OR FANTASY?

摘要

Left ventricular noncompaction (LVNC) is a relatively new form of cardiomyopathy in humans. As with other cardiomyopathies during their emerging phase, it goes by several names including, but not limited to, isolated left ventricular noncompaction, noncompaction cardiomyopathy, noncompaction of the ventricular myocardium, and spongiform cardiomyopathy. The World Health Organization still classifies it as an unclassified cardiomyopathy while the American Heart Association recognized it as a distinct form of cardiomyopathy in 2006.1 The diagnostic criteria vary somewhat from author to author. For example, one says "It is characterized morphologically by a severely thickened, 2-layered myocardium, numerous prominent trabeculations, and deep intertrabecular recesses (figure l).2 Another says it is "characterized by a distinctive ("spongy") morphological appearance of the LV myocardium. Noncompaction involves predominantly the distal (apical) portion of the LV chamber with deep intertrabecular recesses(sinusoids) in communication with the ventricular cavity."1 It is speculated that it results from intrauterine developmental arrest of the normal compaction process of the myocardium during the first trimester leading to the formation of two layers of the myocardium: the compacted and the noncompacted layer. In brief, during embryonic development, the myocardium, when first formed, has deep recesses (trabeculations) that presumably allow for myocardial oxygenation. These recesses disappear (the myocardium compacts) during development as the myocardium becomes vascularized. In LVNC it is hypothesized that the inner myocardium fails to compact.