Morphologic heterogeneity in left ventricular noncompaction resulting in accessory left ventricular chambers.


Left ventricular noncompaction (LVNC) is thought to be a rare type of cardiomyopathy likely because of the arrest of myocardial compaction during the fifth to eighth weeks of gestation. The early myocardium consists of deep trabeculations along the endocardium, made of a spongy meshwork of myocardial fibers, that compact to form the capillary network and myocardium of the mature heart, normally progressing from base to apex and from epicardium to myocardium. Many are of the opinion that LVNC is a result of failure to complete this process, though this has been disputed by others who report that LVNC sometimes presents in patients who have had prior normal echocardiograms that did not demonstrate LVNC. To date, the diagnostic criteria of LVNC is largely based on 2-dimensional transthoracic echocardiogram. Typical echocardiographic findings include a 2-layered appearance of the myocardium with a thin outer layer representing the compact myocardium, and a thicker inner layer representing the noncompacted trabeculum, in continuity with the endocardial surface. Three sets of diagnostic criteria have been proposed. Criteria proposed by Chin et al include: the compact layer to total myocardial thickness ratio is <0.5 in end-diastole in apical or parasternal short axis views. Criteria proposed by Jenni et al include: the ratio of noncompacted to compacted myocardium in parasternal short axis view is >2 at end systole with prominent trabeculations and deep intertrabecular spaces that are perfused by intraventricular blood demonstrated by Doppler imaging, in the absence of other congenital heart disease. Finally, criteria proposed by Stollberger et al include: >3 trabeculations protruding from the left ventricular free wall apically to the papillary muscles, with the intertrabecular spaces perfused from the left ventricular cavity demonstrated by Doppler imaging. However, Kohli et al have called these criteria into question, with a study that showed that only 30% of LVNC met the requirements of all 3 diagnostic approaches. The clinical utility of cardiac MRI in this setting has yet to be rigorously evaluated. There is some evidence that cardiac MRI provides more detailed morphological data in these patients. We present 2 cases of LVNC with atypical left ventricular morphologies in which several imaging modalities were used to assess the appearance of an accessory chamber.

DOI: 10.1161/CIRCHEARTFAILURE.112.969469

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@article{Ezon2012MorphologicHI, title={Morphologic heterogeneity in left ventricular noncompaction resulting in accessory left ventricular chambers.}, author={David S Ezon and Shiraz A Maskatia and Aamir Jeewa and Susan W . Denfield}, journal={Circulation. Heart failure}, year={2012}, volume={5 6}, pages={e94-5} }