Left Ventricular Non Compaction Cardiomyopathy (LVNC)
Left ventricular non compaction (LVNC) is a type of cardiomyopathy which is characterized by the presence of prominent trabeculations in the left ventricle with deep recesses between the trabeculations and a thin compacted myocardial layer. It is the third most frequent cardiomyopathy in children (~9%). Familial disease occurs in 18-50% of adults with isolated LVNC. There is intrafamilial phenotypic variability.
Embryologic: Intrauterine arrest of compaction of the fetal myocardium and subsequent persistence of deep trabecular recesses in the myocardial wall.
Acquired: As it is seen in athletes, pregnancy and patients with sickle cell anemia.
Genetic: Molecular causes: FKBP12 cytoplasmatic protein deficiency with upregulation of the BMP10 gene; upregulation of Notch1-activated protein. Other involved genes include: β-myosin heavy chain, α-cardiac actin, cardiac troponin T, tafazzin, α-Dystrobevin, Lamin A/C, ZASP/LDB3, Dystrophyn, HCN4 and MYH7.
Echocardiographic Findings and Diagnostic Criteria:
Segmental thickening of the left ventricular myocardial wall, with prominent trabeculations and deep recesses.
Jenni Index: Noncompacted to compacted ratio > 2 at end-systole. This is the most validated with pathologic specimens.
Chin Index: Compact layer to distance between epicardial surface to the peak of the trabeculations <0.5.
Sollberger Criteria: Trabeculations, apically to the papillary muscles, with same echogenicity of the myocardium and perfusion of the intetrabecular spaces from the left ventricular cavity
(i) Prominent trabeculations with deep recesses
(ii) Decrease in ratio from MV level to papillary muscle level of the distance from the epicardium to the trough of the trabeculations to the epicardium to the peak of the trabeculations
(iii) Increasing LV wall thickness from base to apex
(iv) Compact layer to distance between epicardial surface to the peak of the trabeculations ≤0.5
(i) Bilayered myocardium with multiple, prominent trabeculations in end-systole
(ii) NC/C ratio of >2 : 1
(iii) Communication with the intertrabecular space demonstrated with color Doppler
(iv) Absence of coexisting cardiac abnormalities
(i) Two-layer myocardium in which the noncompacted layer is thicker than the compacted myocardium
(ii) > 3 prominent trabeculations protruding from the LV wall apical to the papillary muscles
(iii) Perfused intertrabecular spaces by color Doppler
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