Download Ratio trabecular and compact myocardium in the wall of the left

T. Savchuk, V. Zakharova
The ratio trabecular and compact myocardium in the wall of the left ventricle in fetuses
with hypoplasia left heart syndrome.
Introduction. Under hypoplasia left heart syndrome (HLHS) understand a group of
developmental abnormalities of the heart, characterized by hypoplasia of the left chambers, atresia or
stenosis of the aortic and / or mitral opening and hypoplasia of the ascending aorta. Frequency of
occurrence HLHS ranges from 1-8% of all congenital heart defects. In newborns with heart defects,
this anomaly is one of the most frequent causes of death (15-25%). HLHS can be diagnosed in utero.
Not studied the structural features of the left ventricular myocardium. No specific features of the
formation of compact and trabecular myocardium in this abnormality. Not set if the result is HLHS
stenosis (atresia), mitral valve, or the primary genetic defect of left ventricular myocardium.
The purpose of the study. Identify the features of trabecular and compact myocardium in
hypoplastic left heart in fetuses compared with normal myocardium.
Material and methods. We studied 18 fetuses without heart defects and 3 heart syndrome with
hypoplastic left ventricle in gestational age from 19 to 22 weeks. Performed 6-7 measurements
trabecular thickness and compact layer of myocardium in the area of the apex of the heart, in the
middle part, the basis of the heart. Then the ratio was calculated trabecular thickness myocardium to
compact - Myocardial Trabecularity Index (MTI) Conditional boundary between compact and
trabecular myocardium were considered spaces between trabecular deepening of the endothelial lining.
Also measured left ventricular cavity area in different parts of the heart.
Results. At macroscopic examination of hearts from HLHS found that in all three cases, left
ventricular hypoplasia accompanied by aortic atresia. However, in the heart of number 1 and number 2
heart failed to detect the presence of mitral valve opening, while the number 3 heart atrioventricular
connection was missing. At the heart of number 1 LV cavity was reduced at top and extended at the
base. In the heart of the LV cavity number 2 was almost absent at the top, while in the middle of and at
the basis of a small cylindrical shape. Heart number 3 was a very little "sticker" on the right ventricle,
with a faint slit cavity. In microscopy revealed that trabecular in the heart number 1 pass from wall to
wall, creating a three-dimensional chaotic network. At the heart of number 2 trabecular arranged
parallel to the walls, were considerably flattened and often fused together. At the heart trabecular
number 3 as well as all of its structures were drastically reduced and placed parallel to the walls of the
ventricles. In all cases HLHS accompanied by ventricular fibroelastosis. Structural move hearts with
myocardial fibers HLHS had direction, as in normal hearts. Found that on top of the left ventricle, in
the hearts of number 1, 2 absolute thickness of the compact myocardium (CM) is two times higher
than similar data pertaining to CM normal hearts, while the thickness of the heart CM number 3
slightly smaller than in normal hearts. Absolute numbers trabecular myocardium (TM) all three hearts
was significantly lower than normal, and relatively lower own CM. Thus, in the heart of number 1,
which was spongy structure of trabecular, observed an almost complete lack of them at the top: the
thickness of this layer was around 85 ± 19 microns against 1104,9 ± 123,5 mm normal. In observation
number 2, 3 trabeculation apex was significantly higher than in the first case, but also significantly
lower value of this index in normal hearts. MTI on top of the normal is 0,76 ± 24,6, and when HLHS
from 0.029 to 0.28.In the middle of absolute left ventricular thickness in CM hearts 1 and 2 [2023 ±
165, respectively; 2898,4 ± 178,4] also higher than data relating to CM normal hearts [1415,8 ± 94,4].
Absolute numbers CM in the third heart [231 ± 16,5] is much smaller than the thickness of a normal
heart rates. Absolute numbers of TM in the first heart a little bigger than normal, and thicknesses TM
hearts № 2 and 3 are much lower compared to the absolute values of TM rules. In the first and second
heart TM thickness of the middle part [1717 ± 604,3; 923,7 ± 142]. Significantly higher relative values
of the thickness of the top TM [85 ± 19; 758,3 ± 212]. MTI in the middle part of the norm is 1,18 ±
17,8 at HLHS from 0.32 to 0.99.The basis of ventricular absolute thickness of CM in the first [2148,3
± 293,5] and second hearts [2187,2 ± 47,4] higher than data such thickness normal heart [1502,3 ±
154,7]. The third heart contrary thickness CM [984,4 ± 164,3] thinner than a normal heart. Absolute
numbers thickness TM heart rate higher than number 1, [1844 ± 757 vs 1166,6 ± 134,6], while the
second and third below normal hearts [respectively 681,8 ± 44,2; 207 ± 83,2]. In addition, second and
third base hearts trabeculation LV were not significantly different from trabeculation middle part. MTI
LV base normally is 0,78 ± 33,9 and at HLHS from 0.21 to 0.86.Absolute numbers ventricular cavity
area in the area of the top and middle part in all hearts at HLHS much smaller for the same parameters
of normal hearts. And the smallest area of the cavity top (reduced from 59.6 to 690.5 times). While in
the first area of the heart cavities based on increased relative norm of 3.74 times. Cavity third heart at
all sites was the lowest.
Conclusions:
1. In all three hearts with hypoplasia left ventricular observed aortic atresia and in one of them
atresia mitral valve. In one heart ventricular abnormality characterized architectonics trabecular
apparatus that looked like a three-dimensional grid that fills the middle part of the main ventricle.
Trabecular second two hearts were typical longitudinal location.
2. Ventricular shape and size depend on the architecture of TM, and the presence or absence of
mitral valve.
3. In all hearts with HLHS MTI was significantly reduced compared with the norm, the
exclusion is the basis of heart number 1 with mesh structure trabecular.
4. Thickness CM hearts open mitral valve exceeded normal size, whereas with atresia mitral
valve thickness as compact and trabecular apparatus were sharply reduced.