Open atrioventricular canal: symptoms, diagnosis, treatment

The share of the open atrioventricular canal accounts for about 4% of all congenital heart defects. The vice is characterized by underdevelopment of the partitions adjacent to the AV valves and the anomalies of the valves themselves.

Incomplete (partial) form of open atrioventricular canal

The primary different atrial atrial defect is characteristic. AV-valves are formed at one level (normally the tricuspid valve is displaced to the apex of the heart) and attached to the upper edge of the interventricular septum. Cleavage of the mitral valve leaf can be in the form. A small marginal diastasis or reach its base. From the edges of the cleavage, additional chords often attach to the interventricular septum: abnormalities of the papillary muscles are possible. Disturbances of hemodynamics are characterized by regurgitation on the mitral valve and shunting of blood through the defect of the interatrial septum. There is a volume overload of both ventricles, pulmonary hypertension develops (up to the sclerotic phase already in the first years of life). With stenosis of the pulmonary artery, the course of the defect is more favorable, since pulmonary hypertension does not develop.

Characteristics of complaints of lag in physical development, repeated pneumonia, decreased appetite, rapid fatigue in feeding, signs of heart failure in the form of tachypnea, tachycardia. There are stagnant rales in the lungs, the liver is enlarged. The time of appearance of the first signs and the severity of the condition are determined by the severity of mitral insufficiency. With significant regurgitation, the condition of the newborn from the first days is severe, as the pressure increase in the left atrium and the volume of the discharge of blood are significant.

In the physical examination, a left-sided cardiac hump, systolic jitter in the fourth intercostal space and / or above the apex of the heart is detected. Auscultatory, when the AV channel is incomplete, two sounds are heard: the systolic murmur of mitral regurgitation at the apex of the heart and the systolic murmur of the relative pulmonary artery stenosis - the defect of the interatrial septum (ejection noise).

The ECG helps a lot in diagnosis. In most patients, the deviation of the electric axis of the heart to the left is from 0 to 150 s. The corollary of the anomalous formation of the conduction system of the heart is the displacement of the AV node and the bundle of the Hyps posterior to the back, the early departure of the left leg of the nica beam or its hypoplasia. As a sign of volumetric overload of the right ventricle, an incomplete blockade of the right leg of the Heis bundle of the rSR form in lead V1 occurs.

The shape and dimensions of the cardiac shadow on the radiograph are determined by the severity of the mitral valve insufficiency, and therefore the heart shape resembles that of myocardial diseases (increased mainly due to the left divisions).

In the incomplete form of the open AV channel, the signs of the primary atrial septal defect (interruption of the echoes from the interatrial septum) and the anomalies of the mitral valve are echocardiographically detected.

Cardiac catheterization and angiocardiography is performed to determine the degree of pulmonary vascular disease in patients with pulmonary hypertension.

Treatment. Medicamentous treatment is aimed at arresting the signs of heart failure. The vice can be eliminated only in an operative way. Planned intervention is shown at the age of 1-2 years, and with severe mitral insufficiency or general atrium - before. The defect plastic is made and the split valve leaf is reconstructed.

The complete form of the atrioventricular canal of the open atrioventricular canal

The vice includes the primary defect of the interatrial septum, the defect of the interventricular septum immediately below the AV valves and the common AB-ring. There is a shunting of blood at the level of the interatrial and interventricular septum, the insufficiency of AV valves develops. There is a massive overload of the left and right parts of the heart. The pressure in the ventricles is equalized, which leads to the early development of high pulmonary hypertension by the end of the first year of life. In the presence of pulmonary stenosis, the discharge from left to right decreases.

The vice is characterized by a severe course immediately after the birth of the child. Significant deterioration occurs by the end of the first month, when the resistance of the pulmonary vessels decreases and the pulmonary blood flow increases. During this period, the severity of symptoms of heart failure increases. Children are lagging behind in development, repeated pneumonia is not uncommon.

In the physical examination of the cardiovascular system, palpation is detected by systolic trembling. Severe systolic murmur along the left edge of the sternum (defect of the interventricular septum), systolic nocturnal valve failure and a second tone accent over the pulmonary artery are heard.

ECG changes are similar to those in the incomplete form of an open AV channel.

On the roentgenogram, the pulmonary pattern is significantly strengthened along the arterial channel. The heart shadow is usually enlarged by all the cameras. With concomitant stenosis of the pulmonary artery, the pulmonary pattern is normal, and the size of the heart is small.

Echocardiography allows to obtain complete morphological and hemodynamic characteristics of the defect. For surgical treatment, the following information is important: the dimensions of the defects and valve openings, the anatomy of the valves and the state of the papillary muscles, the relative and absolute sizes of the ventricles.

Cardiac catheterization and angiocardiography in the diagnosis of an open atrioventricular canal have now lost their significance. Methods are used to determine the state of the pulmonary vascular bed in the case of high pulmonary hypertension.

Treatment. Medicamentous treatment is aimed at arresting the signs of heart failure. Since the full form of the AV channel rapidly develops high pulmonary hypertension with sclerotic changes in blood vessels, a primary radical correction of the defect is shown - closure with the help of patches of interatrial and interventricular defects and plastic AV valves.

[1], [2], [3], [4]