ventricular septal defect

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Ventricular Septal Defect

 

Definition

A ventricular septal defect is a hole in the wall of the heart (septum) that separates the left lower chamber (left ventricle) from the right lower chamber (right ventricle). The hole allows blood to flow from the left ventricle to the right ventricle instead of entering the aorta for distribution throughout the body. Ventricular septal defect is one of a group of heart problems found in newborn babies that are collectively called congenital heart disease.

Description

The heart has four chambers. The two lower chambers are called ventricles and are responsible for pumping blood. The right ventricle pumps blood to the lungs and the left ventricle pumps blood throughout the body. If there is a hole in the septum that separates the two ventricles, blood from the left ventricle can enter the right ventricle. This blood recycles through the lungs before returning to the left ventricle. This results in less oxygenated blood reaching the body. If the hole is sufficiently large, the lack of oxygen being delivered to the body can cause severe problems, including heart failure and breathlessness. Approximately 0.7% of all babies have a congenital heart defect. Of these, 20% have a ventricular septal defect.

Causes and symptoms

Congenital heart defects are errors in the development of the heart structure. They occur early in the life of the embryo. There is no known cause of congenital heart defects. They can be associated with several diseases, such as German measles (rubella) and Down syndrome. Genetics does not seem to play a role in ventricular septal defect. People with a heart defect do not have an increased chance of passing it on to their children.
Symptoms result from a reduced amount of oxygen going to the body. Symptoms are proportional to the size of the defect. They may appear at any time in the life of the child. In cases where the hole in the septum is very small, few or no symptoms may appear and the child may develop normally. In cases where the ventricular septal defect is large, the newborn will shows signs of heavy breathing, sweating, and feeding difficulties. Children with this defect tire easily. Ventricular septal defect can also result in stunted growth resulting from insufficient oxygen being delivered to the growing body. Children with ventricular septal defect tend to suffer more frequent colds and pneumonia, and have a higher rate of inflammation and infection of the heart (endocarditis).

Key terms

Echocardiogram — An image of the heart produced by an instrument that uses sound waves to create image the heart.
Electrocardiogram — A graph of the heart's beating action.
Endocarditis — An inflammation of the interior lining of the heart that is frequently caused by infectious agents.

Diagnosis

The condition is first suspected based on observation of the child. The physician will listen to the heart with a stethoscope (auscultation) to detect a heart murmur. X rays, electrocardiogram (ECG), and echocardiography can all be used to evaluate ventricular septal defect.

Treatment

Most small holes close without treatment. Often, as the child grows, the hole closes or becomes smaller. If the hole is large or fails to close, the child is usually treated with drugs. Holes that persist and are causing problems in development are corrected by open heart surgery. Usually, surgery is performed after one year of age, but before the child enters school. This allows time for a trial of drug therapy, which could potentially eliminate the need for surgery. The operation is generally safe.

Prognosis

Children with small septal defects tend to develop normally and without any effect on their ability to participate in physical activities. Surgery allows children with larger defects to live nearly normal lives.

Resources

Books

Alexander, R. W., R. C. Schlant, and V. Fuster, editors. The Heart. 9th ed. New York: McGraw-Hill, 1998.

ventricular

 [ven-trik´u-ler]
pertaining to a ventricle.
ventricular septal defect a congenital heart defect in which the opening in the ventricular septum (normal in the fetus) persists after birth, in either the muscular or fibrous portion, most often due to failure of the bulbar septum to completely close the interventricular foramen. This permits flow of blood directly from one ventricle to the other, resulting in bypassing of the pulmonary circulation and varying degrees of cyanosis. Defective valves affecting the flow of blood to and from the heart may also be present.
Abnormal communication between the ventricles in ventricular septal defect. From Dorland's, 2000.

ven·tric·u·lar sep·tal de·fect

Avoid the incorrect form ventriculoseptal.
a congenital defect in the septum (membranous or muscular) between the cardiac ventricles, usually resulting from failure of the spiral aorticopulmonary septum to close the interventricular foramen.

ventricular septal defect

Interventricular septal defect; ventriculoseptal defect, VSD Cardiology A congenital heart defect–CHD in which there is direct communication between the right and left ventricles through a defect in the muscular or fibromembranous septum; VSDs result when there is a lack of growth or failure of the components to align or fuse; simple VSD accounts for 25% of all CHDs;  25% to 40% of VSDs close spontaneously by age 2, 90% by age 10; small VSDs are usually asymptomatic; if large, blood flow direction is determined by systemic vs pulmonary vascular resistance; with time, pulmonary vascular resistance ↑, resulting in pulmonary HTN–PH and R→L shunting Anatomic defects Most VSDs–70% located in the membranous portion of the interventricular septum; the remainder are located in the muscular portion of the septum, below the aortic valve, and at the atrioventricular canal Risk factors for VSD Maternal rubella, other viral illness during pregnancy, poor nutrition, alcoholism, age ≥ 40, DM Severity With major L→R shunting, LV impulse is laterally dsplaced and the RV impulse is weak in absence of PH Heart sounds Holosystolic murmur loudest at the left sternal border, often accompanied by a palpable thrill; mid-diastolic apical rumble due to ↑ flow across the mitral valve; decrescendo diastolic murmur of aortic regurgitation if the VSD undermines the valve annulus; if PH is present, an RV heave and pulsation over the pulmonary trunk is palpable; with PH, the holosystolic thrill and murmur ↓ and a Graham Steel murmur–pulmonary regurgitation–appears EKG Large defects have evidence of left atrial and LV enlargement; with pH!RS axis shift appears Clinical Cyanosis, finger clubbing Imaging CXR–LV enlargement and shunt vasculopathy; with PH, there is marked enlargement of the proximal pulmonary arteries, rapid tapering of the peripheral pulmonary arteries, and oligemic lung fields; other techniques used include 2-D echocardiography with Doppler flow, catheterization and angiography Management Adults with small defects are generally asymptomatic, but have an ↑ risk of infective endocarditis; for adults with large defects surgical closure is indicated if the pulmonary obstructive vascular disease will allow treatment. See Atrial fibrillation, Congenital heart disease. Cf Atrial septal defect.
Ventricular septal defect-functional types
Small-Medium LeftRight Shunts w/o Pulmonary HTN Acyanotic, asymptomatic, grade II-IV/VI pansystolic murmur Management May resolve spontaneously, or be too small to justify repair
Large LeftRight Shunts w/o or w/ Pulmonary HTN Acyanotic, easy fatigability, CHF in infancy, grade II-V/VI pansystolic murmur; hyperactive heart; biventricular enlargement, diastolic murmur at apex; P2 usually accentuated Management Repair required; in infancy for CHF; before age 2 if progressive pulmonary HTN; otherwise, 'electively' between ages 2 and 5

ven·tric·u·lar sep·tal de·fect

(VSD) (ven-trik'yū-lăr sep'tăl dē'fekt)
A congenital defect in the interventricular septum, usually resulting from failure of the spiral septum to close the interventricular foramen.

ven·tric·u·lar sep·tal de·fect

(VSD) (ven-trikyū-lăr septăl dēfekt) Avoid the incorrect form ventriculoseptal.
Congenital defect in septum between cardiac ventricles, usually resulting from failure of spiral aorticopulmonary septum to close interventricular foramen.