Subendocardial Fibrosis in Left Ventricular Hypertrabeculation-Cause or Consequence?

Abstract

Left ventricular noncompaction has been classified as a primary cardiomyopathy with a genetic origin. This condition is morphologically characterized by a thickened, two-layered myocardium with numerous prominent trabeculations and deep, intertrabecular recesses. Recently, it has become clear that these pathological characteristics extend across a continuum with left ventricular hypertrabeculation at one end of the spectrum.The histological findings include areas of interstitial fibrosis.We present a case of left ventricular hypertrabeculation which presented as sudden infant death syndrome. Histologically areas of subendocardial fibrosis was prominent and we propose that this entity may be a hidden cause of arrhythmic death in some infants presenting as sudden infant death syndrome., with areas of subendocardial fibrosis as possible arrhythmogenic foci.

Fetal Ventricular Hypertrabeculation/Noncompaction: Clinical Presentation, Genetics, Associated Cardiac and Extracardiac Abnormalities and Outcome

“…Endocardial fibrosis is a frequently found abnormality in adults and children with LVHT [11,21,33]. Endocardial fibrosis may enhance the detection rate of LVHT since the endocardial boundary and the trabeculations become more clearly visible when investigating the heart by ultrasound.…”

“…Endocardial fibrosis may lead to diastolic dysfunction, restrictive filling pattern of the left ventricle and heart failure. Involvement of the cardiac conduction system by the endocardial fibrosis might promote arrhythmia [33]. Probably, the endocardium plays a role in the pathogenesis of LVHT: Animal experiments have shown that endocardial Notch1 plays a crucial role in regulating ventricular trabeculations and that Fkbp1a-mediated regulation of Notch1 plays an important role in intercellular communication between endocardium and myocardium, which is crucial in controlling the formation of the ventricular walls [10].…”

Noncompaction in Mitochondrial Myopathy: Visible on Microscopy but Absent on Macroscopic Inspection

“…Histological appearance of the trabeculations has been previously reported in some cases [4]. In a child with sudden infant death syndrome, autopsy revealed LVHT, and histological work-up of the myocardium showed marked subendothelial fibrosis [4].…”

“…In a child with sudden infant death syndrome, autopsy revealed LVHT, and histological work-up of the myocardium showed marked subendothelial fibrosis [4]. Subendocardial fibrosis was made responsible for the presumed arrhythmias leading to sudden cardiac death [4].…”

Myocardial Infarction as Typical Presentation of Noncompaction Cardiomyopathy

“…Ключевым механизмом этих проявлений считают неполноценное кровоснабже-ние миокарда под некомпактным слоем, лишенным коронарного кровотока [9]. Как следствие этой ише-мии описывают не только мелкоочаговый субэндо-кардиальный фиброз [11], но и достаточно крупные зоны фиброза, различимые при МРТ [12,13].…”