Paediatric dilated cardiomyopathy with and without endocardial fibroelastosis – a pathological analysis of 89 explants

Abstract

Heart failure due to dilated cardiomyopathy is a major indication for paediatric cardiac transplantation. Endocardial fibroelastosis is a recognised pathological finding of unknown prognostic significance in paediatric dilated cardiomyopathy. To evaluate the nature of the association between left ventricular endocardial fibroelastosis and paediatric dilated cardiomyopathy, we reviewed surgical pathology reports of dilated cardiomyopathy explants (1986–2016) in order to characterise the pathological findings and to compare and contrast their frequency among four age groups: less than 1 year; 1–5 years; 6–10 years; and greater than 11 years. The 89 explants (47 males and 42 females) were all characterised by increased weight and left ventricular chamber dilatation without increased wall thickness. Ninety-five per cent of the specimens in the two youngest subsets had left ventricular endocardial fibroelastosis. Compared to the oldest age group, recipients aged 1–5 years had a 6-fold increase and those younger than 1 year a 19-fold increase in the odds of observing left ventricular endocardial fibroelastosis. Explants with and without endocardial fibroelastosis were otherwise phenotypically similar. In paediatric dilated cardiomyopathy endocardial fibroelastosis is a very common pathological finding, especially in infants and young children. We propose that the descriptive, clinico-pathological designation “Dilated Cardiomyopathy with Endocardial Fibroelastosis” should be adopted to facilitate future investigation into the potential prognostic/therapeutic significance of left ventricular endocardial fibroelastosis.

High ejection fraction of the left ventricular trabecular layer of the human heart

“…If trabeculations are included in the LV blood pool and the IR and the CC both operate at an EF of 60%, the greater the trabecular tissue volume, the lower the measured EF will be (Figure 5a , Data S1 ). In failing hearts, the ventricular wall can have much subendocardial fibroelastosis and this can reduce the compliance of the trabecular layer (O'Rourke, 2023 ; Reyes et al., 2022 ; Takamatsu et al., 2020 ). Varying the EF of an excessive trabecular layer from 10% (extremely reduced compliance) to 90%, while keeping the CC EF at 60%, shows the total EF to increase from below 40% to above 70% (Figure 5b , Data S1 ).…”

Endocardial Fibroelastosis as an Independent Predictor of Atrioventricular Valve Rupture in Maternal Autoimmune Antibody Exposed Fetus: A Systematic Review with Clinicopathologic Analysis

“…EFE is a non-specific, protracted response to myocardial wall stress that frequently becomes worse over time and eventually leads to heart failure [ 2 ]. EFE is one of the extranodal manifestations of neonatal lupus, whose natural history and pathogenesis are less understood [ 3 , 4 , 22 , 23 ].…”

“…Most fibroblasts in EFE are proposed to originate from embryonic epicardial-derived mesenchymal cells. A simultaneous effect on the endocardium is thought to occur during infancy when compensatory mechanisms are initiated to counteract cardiac dysfunction brought on by myocyte injury, which encourages fibro-elastotic growth [ 2 ].…”

“…However, extranodal neonatal cardiac lupus, such as myocarditis with endocardial fibroelastosis (EFE), results in neonatal or late-onset dilated cardiomyopathy and subsequent valvar regurgitation. EFE is a non-specific, protracted response to myocardial wall stress that often worsens over time and leads to heart failure [ 2 ]. The effect of maternal autoantibodies on the endocardium, causing chordal rupture and resulting in severe regurgitation, is rarely studied, with only a few case reports or series.…”