Ventricular septal defect: symptoms, diagnosis, treatment

Ventricular septal defect occurs in 15-20% of all congenital heart defects. Depending on the location of the defect, perimembranous (in the membranous part of the septum) and muscular defects are distinguished, by size - large and small.

Large defects are always located in the membranous part of the septum, their dimensions exceed 1 cm (i.e. more than half the diameter of the aortic orifice). Hemodynamic changes in this case are determined by the degree of blood shunting from left to right. The severity of the condition, as with other defects with blood shunting 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 pulmonary circulation and transfer pressure (i.e. pressure transmitted from the aorta to the pulmonary artery according to the law of communicating vessels), since large defects are often located subaortically. The subaortic location of the defect contributes to the fact that the discharge jet exerts a hemodynamic impact on the aortic cusps, damages the endocardium, creating conditions for the addition of an 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). Rapid development of pulmonary hypertension can subsequently lead to cross-flow and then reverse flow through the defect.

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Symptoms of Ventricular Septal Defect

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

Children with ventricular septal defect are often born with normal body weight and then gain weight poorly. The cause of grade I-II hypotrophy is constant malnutrition (alimentary factor) and hemodynamic disturbances (left-to-right blood flow leads to pulmonary hypovolemia). Sweating is characteristic due to the release of retained fluid by the skin and hypersympathicotonia in response to heart failure. The skin is pale with slight peripheral cyanosis. An early symptom of heart failure is dyspnea of the tachypnea type with the participation of accessory muscles. Often there is an obsessive cough, which intensifies with a change in body position. A ventricular septal defect with a large arteriovenous discharge is accompanied by congestive wheezing, and often repeated pneumonia.

Physical examination of the cardiovascular system visually reveals a bisternal keel-shaped cardiac "hump" formed by an enlarged right ventricle ("Davis's chest"). The apical impulse is diffuse and intensified; a pathological cardiac impulse is determined. Systolic thrill can be detected in the third-fourth intercostal space on the left, indicating a blood shunt into the right ventricle. The absence of thrill is a sign of an initially small shunt or its reduction due to high pulmonary hypertension. The boundaries of relative cardiac dullness are expanded in both directions, especially to the left. The right boundaries of relative cardiac dullness increase by percussion by no more than 1-1.5 cm, since the "rigid" structures of the mediastinum do not create an obstacle. A rough, scraping systolic murmur is heard, associated with the first tone, with the maximum listening point in the third or fourth intercostal space (less often in the second or third) to the left of the sternum; the second tone above the pulmonary artery is accentuated, often split.

In most cases, from the first days or months of life, the clinical picture shows signs of total heart failure: enlargement of the liver and spleen (in children in the first years of life, the spleen enlarges in conjunction with the liver).

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

With a defect of the interventricular septum in the muscular part (Tolochinov-Roger disease) there are no complaints. There are no clinical manifestations of the defect, with the exception of a scraping systolic noise of medium intensity, heard in the fourth-fifth intercostal space. Noise is not conducted from this point, its intensity may decrease in a standing position. Pulmonary hypertension does not develop, spontaneous closure of the defect is possible.

Complications of ventricular septal defect

A complication of the ventricular septal defect is Eisenmenger's 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 main defect (shunt noise) may weaken or disappear completely, the accent of the second tone on the pulmonary artery increases, often acquiring a "metallic" shade of sound. The vessels of the pulmonary circulation can undergo morphological changes, become sclerotic - the sclerotic stage of pulmonary hypertension occurs. The direction of blood discharge can change: blood begins to be shunted from right to left, and the pale defect is transformed into a blue defect. Most often, such a situation occurs with late detection of the defect, with its natural course, i.e. in the absence of timely cardiac surgery. With the development of Eisenmenger's syndrome, patients with congenital heart disease become inoperable.

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How is ventricular septal defect recognized?

The ECG reveals a rightward deviation of the electrical axis of the heart, signs of combined ventricular overload. The appearance of signs of right ventricular hypertrophy in the left chest leads often correlates with high pulmonary hypertension (more than 50 mm Hg).

X-ray examination reveals hypervolemia of the pulmonary circulation, an increase in the size of the heart due to both ventricles and atria. A bulge of the pulmonary artery arch along the left contour of the heart is detected.

The main diagnostic sign is direct visualization of the defect using echocardiography. Scanning the heart in several sections allows determining the size, location and number of defects. Using Doppler mapping, the magnitude of the discharge is determined.

Cardiac catheterization and angiocardiography have lost their significance in simple ventricular septal defects. The studies are indicated if it is necessary to clarify the state of the pulmonary circulation in high pulmonary hypertension.

Differential diagnosis must be carried out with all defects that may be complicated by high pulmonary hypertension.

Treatment of ventricular septal defect

The treatment tactics are determined by the hemodynamic significance of the defect and the known prognosis. In patients with heart failure, it is advisable to start conservative therapy using diuretics and cardiac glycosides. Children in the second half of life with small ventricular septal defects without signs of heart failure, without pulmonary hypertension or developmental delay, as a rule, do not undergo surgery. Surgery is indicated for pulmonary hypertension and delayed physical development. In these cases, surgery is performed from the first half of life. In children over one year old, surgery is indicated if the ratio of pulmonary and systemic blood flow is more than 2:1. At an older age, cardiac catheterization is usually performed to clarify the indications for correction of the defect.

In case of large defects, it is necessary to perform open heart surgery under artificial circulation at the earliest possible stage (in infancy or early childhood). Plastic surgery is performed with a xenopericardial patch using transatrial 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 complicate the correction of the defect. The operation of choice is closure of the defect under artificial circulation. The risk of surgery increases in children under 3 months in the presence of multiple ventricular septal defects or concomitant serious developmental anomalies of other organs and systems. In recent years, the popularity of the transcatheter closure of the ventricular septal defect using the Amplatzer occluder has increased. The main indication for this procedure is multiple muscle defects.