Defect of the interventricular septum: symptoms, diagnosis, treatment

Defect of the interventricular septum occurs in 15-20% of cases from all congenital heart defects. Depending on the localization of the defect, peremembranous membranes (in the membranous part of the septum) and muscular defects are distinguished, in size - large and small.

Large defects are always located in the membranous part of the septum, their dimensions exceed 1 cm (ie, more than half the diameter of the aortic orifice). Hemodynamic changes in this case determine the degree of discharge of blood from left to right. The severity of the condition, as with other vices with a discharge of blood from left to right, directly depends on the severity of pulmonary hypertension. The severity of pulmonary hypertension, in turn, is determined by two factors: hypervolemia of the small circle of blood circulation and transmission pressure (ie, pressure transmitted from the aorta to the pulmonary artery by the law of communicating vessels), since large defects are more often located suborally. The subordinal location of the defect contributes to the fact that the discharge jet has a hemodynamic impact on the aortic valves, damages the endocardium, creating conditions for the attachment of the infectious process. The discharge of blood into the right ventricle, and then into the pulmonary artery system occurs under high pressure (up to 100 mm Hg). The rapid development of pulmonary hypertension can subsequently lead to a cross, and then a reverse discharge through the defect.

[1], [2], [3], [4], [5], [6], [7]

Symptoms of an interventricular septal defect

The vice manifests in the first weeks and months of life. In a third of cases, it determines the development of severe heart failure in newborns.

Children with a defect of the interventricular septum are born more often with normal body weight, and then poorly gain weight. The cause of grade I-II hypotrophy is a constant malnutrition (alimentary factor) and a hemodynamic disorder (discharge of blood from left to right leads to hypovolemia of the small circle of blood circulation). Characterized by sweating due to the allocation of delayed skin and hypersympathicotonia in response to heart failure. The skin is pale with little peripheral cyanosis. The earliest symptom of heart failure is dyspnoea by the type of tachypnea with the involvement of an auxiliary musculature. Often there is an obsessive cough, which increases when the position of the body changes. Defect of the interventricular septum with a large arteriovenous discharge is accompanied by stagnant wheezing, and often repeated pneumonia.

In the physical examination of the cardiovascular system, visually detect the bisternal keeled heart "hump", formed by the increase in the right ventricle ("Davis's chest"). Apical thrust diffused, strengthened; a pathological heartbeat is detected. You can detect systolic tremor in the third to fourth intercostal space to the left, indicating the discharge of blood into the right ventricle. The absence of jitter is a sign of initially small discharge or its decrease due to high pulmonary hypertension. The boundaries of relative cardiac dullness are widened in both directions, especially to the left. The right boundaries of relative cardiac dullness increase percussion by no more than 1-1.5 cm, because the "rigid" structures of the mediastinum do not create obstacles. A sibilant, timbre systolic noise associated with I tone is listened to, with a maximum listening point in the third to fourth intercostal space (less often in the second or third intercostal space) to the left of the sternum, the second tone over the pulmonary artery accentuated, often split.

In most cases, from the first days or months of life in the clinical picture, signs of total heart failure are expressed: an increase in the liver and spleen (in children of the first years of life, the spleen increases with the liver).

With the natural course of the disease, the condition and well-being of children improve with age, due to a decrease in the size of the defect with respect to the increased total volume of the heart, and covering the defect with the aortic valve.

With a defect of the interventricular septum in the muscular part (Tolochinov-Roger's disease), there are no complaints. Clinical manifestations of the defect are absent, except for scraping systolic murmur of medium intensity, which is heard in the fourth to fifth intercostal space. From this point noise is not carried out, its intensity can decrease in a standing position. Pulmonary hypertension does not develop, there may be a spontaneous closure of the defect.

Complications of an interventricular septal defect

Complication of the defect of the interventricular septum is Aizenmenger syndrome, characterized by a significant increase in pressure in the pulmonary artery, when it becomes equal to or exceeds the pressure in the aorta. In this hemodynamic situation, the noise of the primary defect (discharge noise) may subside or completely disappear, the accent of the 2nd tone on the pulmonary artery increases, often acquiring a "metallic" tone of sound. Vessels of a small circle of blood circulation can undergo morphological changes, to be sclerized - the sclerotic stage of pulmonary hypertension occurs. The direction of the discharge of blood can change: the blood begins to be discharged from right to left, and the vice of a pale type is transformed into a blue-type flaw. Most often, a similar situation occurs when the late detection of a defect, with its natural flow, i.e. In the absence of timely cardiac care. With the development of the Aizenmenger syndrome, patients with congenital heart disease become inoperable.

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How is the defect of the interventricular septum recognized?

On ECG, the deviation of the electric axis of the heart to the right, signs of combined overload of the ventricles. The appearance of signs of hypertrophy of the right ventricle in the left thoracic leads is often correlated with high pulmonary hypertension (more than 50 mm Hg).

Radiographic examination allows us to identify hypervolemia of the small circle of blood circulation, increase in the size of the heart due to both ventricles and atria. Detect the swelling of the pulmonary artery along the left contour of the heart.

The main diagnostic feature is the direct visualization of the defect with the help of echocardiography. Scanning the heart in several sections allows you to determine the size, location and number of defects. Using the Doppler mapping, the reset value is set.

Cardiac catheterization and angiocardiography with simple defects of the interventricular septum have lost their significance. Researches are shown, if it is necessary to specify a condition of a small circle of a circulation at a high pulmonary hypertension.

Differential diagnosis should be carried out with all the defects that can be complicated by high pulmonary hypertension.

Treatment of an interventricular septal defect

Treatment tactics determine the hemodynamic significance of the defect and the known prognosis. In patients with heart failure, it is advisable to start conservative therapy with diuretics and cardiac glycosides. Children of the second half of life with small defects of the interventricular septum without signs of heart failure, without pulmonary hypertension or delayed development, as a rule, do not operate. Surgical intervention is indicated for pulmonary hypertension and delayed physical development. In these cases, the operation is carried out from the first half of life. Children over the age of a year of surgery are indicated at a ratio of pulmonary and systemic blood flow more than 2: 1. In the elderly, cardiac catheterization is usually performed to clarify the indications for correction of the defect.

For large defects, it is necessary to perform an operation on the open heart in conditions of artificial circulation at the earliest possible time (during infancy or in early childhood). Carry out the plastic with a patch of xenopericardium, using trans-atrial access (without ventriculotomy, i.e., with minimal myocardial trauma).

Palliative intervention (narrowing of the pulmonary artery to limit pulmonary blood flow) is performed only in the presence of concomitant defects and anomalies that make it difficult to correct the defect. The operation of choice is the closure of the defect in conditions of artificial circulation. The risk of surgery increases in children up to 3 months in the presence of multiple defects of the interventricular septum or associated serious anomalies in the development of other organs and systems. In recent years, the popularity of the technique of the transcatheter closure of the interventricular septal defect with the help of the Amplatzer occluder has increased. The main indication for this procedure is multiple muscle defects.