Inter ventricular septal deffect
The inter ventricular septal deffect is one of the most common heart problem . It is diagnosed in 10-30% of children with congenital heart disease. According to medical statistics, for every thousand of births, two children are born with ventricular septal defect. Inter ventricular septum, as follow from its name, divides the left and right ventricles of the heart. Normally, there are no holes in this partition.
If there is an opening in the septum, it creates an opportunity for blood to flow from one ventricle to another. The pressure in the left ventricle is always higher because it is responsible for the release of blood into the systemic circulation, and hence left ventricle has stronger musculature than right one. Therefore, the presence of the hole in the ventricular sept allows the blood flow from the left into the right ventricle, i.e., from the systemic into the pulmonary circulation. The volume of blood in pulmonary is raised and overloaded compared to the norm. Constant high pressure on the vessel walls leads to the development of a spasm and walls of blood vessels might became thick like during development of MS. All these changes might lead to increased pressure in the pulmonary circulation to such extent that it begins to exceed the pressure in a systemic circulation.
And then the process is reversed: there is a discharge of blood from the right ventricle to the left. At this stage the patient develops cyanosis with such symptoms as blue lips, nasolabial folds and the nail plate.
Ventricular septal defect is one of the inherited pathological conditions in babies that are often resolved spontaneously. Thus, in the first month of life, approx. 80% of the total number of holes, are closed spontaneously. In later periods, there is also a possibility that the defect will go away, although it might happen less frequently. Spontaneous closure of the hole is carried out by the muscular layer of the inter ventricular septum and it is happen more often for those holes that are located on the partition below the aorta.
Localization of the holes is of great importance, since it has an impact on the function of surrounding structures and conductive system of the heart.
The core structure of the inter ventricular septum is the connective tissue, surrounded by muscular tissue. Three zones could be identified in the septum : input zone, trabecular zone and output zone.
Accordingly, inter ventricular septal defects can be identified as following:
- perimembrane defects are the most common type of defects. They are localized in the muscular walls of the surrounding membranous part. Deficiency of muscle tissue can occur in any department, but one of the edges of the hole will certainly formed by connective tissue. Typically, this is part of the membranous aortic valve ring. These defects can form in any part of the septum.
- podarterialnye defects. As the name implies, in this case, the hole in the interventricular septum is located under the wings aortic and pulmonary artery, the output of the partitioning
- muscular defects. Their edges are composed entirely of muscle tissue. They can be formed in any part of the walls, there are multiple and / or combined with membranous defects.
With regard to the size of the septum defect, the septal holes are measured in relation to the diameter of the aorta. Naturally, the smaller hole, the less harm is caused to the baby.
If the size of the hole diameter not more than ¼ of the aorta (not exceed 1 cm in diameter) , such defect (called Tolochinova-Rouge syndrome) considered to be too small to be treated surgically. With dimensions comparable to half the diameter of the main blood vessel, the defect is considered as an average, and only those that exceed this number are classified as large ventricular septal defects.
Small defects (represent 30-40% total number of the ventricular septal defects) have a tendency to self-closing. The ECG may not detect a pathology or symptoms of increased load on the left ventricle. Therefore, the ultrasound, which might detect blood flow between the ventricles, is used for diagnostic purposes. A cardiac catheterization and angiography are performed to confirm the preliminary suggested diagnosis. The physiological development of children with small ventricular septal defects is going well, even though during the first week of life it is possible to hear a rough systolic murmur. In older age this disease may cause a fatigue during exercise. The closure of the defect could occur late, at the age of 4-5 years. Such kids should be supervised by a cardiologist, but surgery usually is not recommended for them.
Large ventricular septal defects may be dangerous for a child's life in the first weeks of his/her life, because developing heart failure can lead to a lagging behind in development, generate difficulties in feeding, sucking reflex disturbances and shortness of breath. A child with large septal defect is subject to frequent colds with a propensity for pneumonia.
Te inspection of these children reveals a characteristic protrusion of the chest is visible in the area of the heart and a tremor during systole ( contraction of heart muscle). Shortness of breath gradually became noticeable, even at rest, Functional changes in lung, problems in liver function and swelling of the lower extremities are became clearly noticeable.
Surgical treatment of large ventricular septal defects. If a child has signs of heart failure, the surgery is suggested as early as possible, in the first three months of the baby’s life. If the baby can wait, however, the decision to proceed with surgery should be based on the measurements of the pressure in the pulmonary circulation. In cases where the pressure in the pulmonary arteries are not high, parent should consider to postpone the surgery until 1 year because there are chances for self-imperforate ventricular septal defect. Sometimes it is possible to postpone surgery even until the age of 5 years.
The surgery is performed using the heart-lung machine. The most benign and convenient way to reach the inter ventricular septum is through the right atrium. In cases where it is feasible, surgeons will use the access via the left atrium, aorta or pulmonary artery. If size of defect is allowed , it will be stitched. If a "patch" is used, a synthetic material or small cuttings are taken from the patient's pericardium. Using a special equipment, the hole is edged all around by U-shaped stitches and the patch is checked for leaks.
In some cases, the operation is partial so-called palliative surgery. The goal of this method is just narrowing of the diameter of the pulmonary artery. For this, through the opening in the thorax, through the pericardium, the surgeon is making an access to pulmonary artery, on which he impose a ligature (a thick silk thread) and tie it, narrowing its diameter. Procedure is similar to the imposition of the cuff. The extend of the narrowing of the pulmonary artery is determined on the basis of several vital parameters resulted from the surgery-- general blood pressure and particularly in the pulmonary artery and observing the total blood circulation.
Surgery to remove ventricular septal defects are performed in the large Cardiology Centers only, by the professionals who have extensive experience. Heart Center in "Sheba" Medical Center performed numerous such surgery, which allowed us accumulate a long and successful experience. Always produce favorable results noticeable in the short - and the long-term future.