Three atrial heart – congenital heart disease

Three atrial heart – congenital heart disease

Triatrial heart is a congenital heart defect in which there is a fibromuscular membrane in the left or right atrium, dividing the atrial cavity into two chambers.
The defect rate is 0.1 – 0.4% of all congenital heart defects. The gender distribution shows a slight predominance for males and is a ratio of 1.5: 1. Vice was first described by the Church in 1868.
The left atrial heart is more common, when the membrane divides the left atrium into the posterior superior, an additional cavity that receives the pulmonary veins, and the anteroinferior cavity itself, the left atrial cavity itself, which communicates with the left atrial appendage and the mitral valve. More than 90% of cases of the left atrial chambers communicate with each other – through one central or eccentral opening in the abnormal intra-atrial diaphragm or through several small openings (fenestra). From 5 to 10% of cases show the absence of communication between the accessory chamber and the proper left atrium. In such cases, there is communication with the right atrium directly through the atrial septal defect or indirectly through an abnormal pulmonary venous connection.
Classification E. Loeffler 1949 left tricyclic heart.
He proposed to distinguish 3 types of defect:
Type 1 defect – there are no messages between the chambers of the left atrium;
Type 2 defect – in the membrane dividing the atrium, there are one or more small holes, but their total area is insufficient to ensure blood flow;
Type 3 defect – there is a hole in the membrane through which blood flows freely from the upper chamber to the lower one.
In the first type of defect, when there is no communication between the chambers of the left atrium, blood circulation in the fetus is possible only if there is an atrial septal defect. In this case, blood from the upper-posterior chamber of the left atrium enters through part of the defect into the right atrium, and then through the lower part of the same defect, returns to the lower part of the left atrium. Under these conditions, in the right atrium, arterial blood from the upper posterior part of the left atrium mixes with venous blood and enters the left ventricle. Then, not arterial oxygen-rich blood enters the systemic circulation, but a mixture of arterial and venous blood. Oxygen starvation of the tissues of the whole organism is created. The severity of the patient’s condition depends on the size of the interatrial communication.
Narrow communication leads to early congestion in the pulmonary circulation, develops venous pulmonary hypertension with right ventricular failure.
The right atrial heart is extremely rare. In this defect, the membrane divides the cavity of the right atrium into the proximal and distal chambers. Several options for the location of the membrane in relation to the vessels flowing into the right atrium are described. Most often, the upper chamber can receive blood from both vena cava, the coronary sinus, the lower chamber communicates with the right ventricle through the tricuspid valve and with the right atrial appendage. The right three-chambered heart arises as a result of pathological preservation or excessive proliferation in the process of embryorenesis of the valves of the venous sinus. Defects of various sizes in the membrane allow communication between the chambers of the right atrium.
Clinic.
The manifestations of the left atrial heart are varied. They depend on the size of the defect in the membrane and the created blood currents between the atria, as well as the presence of other cardiac abnormalities. The time of appearance of the first signs of a defect depends on the degree of stenosis. With a small hole, they occur almost from birth: repeated respiratory infections and pneumonia, peripheral cyanosis, physical retardation, obsessive cough, shortness of breath, wheezing in the lungs (refractory to cardiac glycosides and diuretics), rarely, but possibly, hemoptysis, then hepatomegaly appears , swelling of the face and legs. The life expectancy of such patients is no more than 6 months. If the hole in the membrane between the chambers of the left atrium is more than 7 mm, the development of circulatory disorders occurs more slowly. With large message sizes, the first manifestations of the defect are possible at school age and later. In such cases, a false impression of acquired heart disease is created. The most common symptoms in adults are dyspnea, hemoptysis, and orthopnea, which mimic mitral stenosis. Group III patients often survive to adulthood with little or no symptoms. The onset of symptoms occurs secondary to fibrosis and calcification of the membrane opening. The anomaly may manifest as atrial arrhythmias or cerebral and systemic embolism due to a thrombus in the dilated accessory atrial chamber, pulmonary artery thrombosis.
Several cases of pulmonary edema during childbirth have been reported in young women in whom the left tri-atrial heart was not initially diagnosed.
Differential diagnosis in children is carried out with lung diseases, respiratory distress syndrome of newborns, primary pulmonary hypertension, total abnormal drainage of pulmonary veins with venous obstruction, congenital mitral stenosis, left atrial tumor (myxoma); in adults, lung diseases, mitral stenosis are primarily excluded.
Diagnostics of the left three-atrial heart. The vice does not have manifestations specific only to it. Only the auscultatory picture of mitral valve stenosis in a patient with moderate cyanosis and no enlargement of the left atrium can indicate the possibility of a defect. On the ECG in children there is a sharp deviation of the electrical axis of the heart to the right, signs of pronounced hypertrophy of the right ventricle; deep negative T waves in the right chest leads, less often in II, III, aVF – signs of subendocardial ischemia of the right ventricular myocardium with high pressure in it. It is possible, but not always, the appearance of signs of left atrial hypertrophy. In adult patients with a large opening, signs of right ventricular overload are less pronounced. On the roentgenogram, the shadow of the heart in adults may be normal; in oblique projections, there may be an increase in the right heart. There may be an increase in the pulmonary pattern along the venous bed, expansion of the pulmonary artery trunk, dilatation of the left atrial appendage, but the left atrium itself is not always enlarged. The main diagnostic method for the tricyclic heart is transthoracic and transesophageal (PE) echocardiography. The membrane in the atrium can be visualized from various approaches – the four-chambered apical, subcostal, and parasternal. Often it looks like a structure prolapsing towards the mitral valve. Dilation of the right heart and tricuspid valve insufficiency, increased pressure in the pulmonary artery can be determined. Doppler echocardiography reveals turbulent blood flows through the membrane, allows you to measure the transmembrane pressure gradient and maximum flow rate, which is important in assessing the severity of the defect. Severe obstruction is indicated by a maximum Doppler velocity greater than 2 m / s. EchoCG in three-dimensional mode (3D-EchoCG) improves the quality of visualization, gives information about the size of the holes in the membrane and its morphology. Transesophageal echocardiography is a reliable method for diagnosing a defect. Intracardiac echocardiography may also be used. The use of multidetector spiral computed tomography, MRI of the heart provides additional information about the state of the coronary arteries before surgical correction of the tricycle heart, allows us to assess the number and size of holes in the membrane and identify concomitant heart defects. Cardiac catheterization is rarely used to diagnose a defect.
Treatment. The main method of treating the defect is surgical, resection of the membrane that obstructs the flow of blood inside the left atrium, and closure of the atrial septal defect. Balloon dilatation of the narrowed opening in the membrane is possible during cardiac catheterization if the catheter can be inserted into the left atrium. In cases of a very serious condition, the operation takes on the importance of emergency intervention, as the only possible measure to save the patient’s life. As such, it is most often performed in young children.

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