Thickness and Ratio of Noncompacted and Compacted Layers of the Left Ventricular Myocardium Evaluated in 56 Normal Fetuses by Two-Dimensional Echocardiography.

Lei Sun,Enfa Zhao,Yajuan Wei,Baomin Liu,Chunmiao Kang

doi:10.1155/2019/3726846

Abstract

The thickness and ratio of noncompacted and compacted layers of the left ventricular (LV) myocardium in the normal fetus were investigated by fetal echocardiography. We aimed to investigate the compaction process of the LV myocardium during the normal gestation period and provide reference for echocardiographic diagnosis of a fetus with ventricular myocardium noncompaction. A total of 56 pregnant women in the gestational period of 23–30 weeks were included. Complete fetal echocardiography was performed with system ultrasonographic examination to exclude congenital heart malformation or extracardiac malformation. All 56 fetuses showed normal development. In the short-axis view of the fetal heart, the LV wall was divided into an upper and lower section at the level of the papillary muscle. Each section was then further divided into four segments, namely, anterior, posterior, lateral, and inferior wall. Thus, the LV wall was divided into eight segments. The thickness of the ventricular noncompacted and compacted layers and the ratio of the ventricular noncompacted to compacted layers of these segments at end-systole were measured and calculated. In echocardiography, the fetal LV myocardium is a two-layered structure: the endocardial noncompact myocardium (NC) with higher echo and the epicardium compact myocardium (C) with lower echo. The noncompacted layer is thinner than the compacted layer in the anterior wall, but thicker than the compacted layers in the posterior, lateral, and inferior wall. With respect to the upper and lower sections of the LV myocardium, the noncompacted layer in each segment of the upper section is thinner than that in each segment of the lower section, whereas the compacted layer of the upper section is thicker than that of the lower section. This study suggests that the densification of the fetal LV myocardium occurs gradually from base to apex and from the anterior to lateral, posterior, and inferior walls. This finding aids in further understanding the process of myocardial densification and provides a diagnostic reference for noncompaction of noncompaction cardiomyopathy (NCCM).

Highlights

Noncompaction cardiomyopathy (NCCM) is a rare cardiomyopathy that is characterized by excessively prominent trabeculae in the biventricular and deep intertrabecular recesses [1]
The muscular layer of the left ventricular (LV) wall of the fetal heart can be divided into two layers according to the ultrasound image, that is, the compaction layer and noncompaction layer
NCCM is an increasingly recognized type of cardiomyopathy with the presence of an extensive trabeculated myocardium separated into two distinct layers: noncompact myocardium (NC) and C [12, 13]

Summary

Introduction

Noncompaction cardiomyopathy (NCCM) is a rare cardiomyopathy that is characterized by excessively prominent trabeculae in the biventricular and deep intertrabecular recesses [1]. Noncompaction of ventricular myocardium is believed to indicate an arrest in endomyocardial morphogenesis in the embryo [2]. The main pathological change is that the honeycomb-like reliefs form the inner layer of the ventricular structure, which divides the ventricular chamber into several small communicating ventricular cavities [3]. NCCM has three classical clinical presentations, namely, heart failure, arrhythmias, and embolic events [4, 5]. Clinical presentation is highly variable and may range from incidental findings in asymptomatic patients to unexplained end-stage heart failure. Early diagnosis and treatment of patients with NCCM is crucial as high morbidity and mortality caused by lifethreatening conditions [7]. Echocardiography is regarded as the first-choice diagnostic modality to determine myocardial pathologies [8].

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