ventricular septal defect

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.

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defect /de·fect/ (de´fekt) an imperfection, failure, or absence.defec´tive

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acquired defect  a non-genetic imperfection arising secondarily, after birth.

aortic septal defect  a congenital anomaly in which there is abnormal communication between the ascending aorta and pulmonary artery just above the semilunar valves.

atrial septal defects , atrioseptal defects congenital anomalies in which there is persistent patency of the atrial septum, owing to failure of the ostium primum or ostium secundum.

Atrial septal defects; cutaway composite view showing possible locations of ostium primum and secundum defects in the right atrium.

birth defect  one present at birth, whether a morphological defect (dysmorphism) or an inborn error of metabolism.

congenital defect  birth d.

congenital ectodermal defect  anhidrotic ectodermal dysplasia.

cortical defect  a benign, symptomless, circumscribed rarefaction of cortical bone, detected radiographically.

endocardial cushion defects  a spectrum of septal defects resulting from imperfect fusion of the endocardial cushions, and ranging from persistent ostium primum to persistent common atrioventricular canal; see atrial septal d. and atrioventricularis communis.

fibrous cortical defect  a small, asymptomatic, osteolytic, fibrous lesion occurring within the bone cortex, particularly in the metaphyseal region of long bones in childhood.

filling defect  any localized defect in the contour of the stomach, duodenum, or intestine, as seen in the radiograph after a barium enema.

genetic defect  see under disease.

luteal phase defect  inadequate secretory transformation of the endometrium during the luteal phase of the menstrual cycle; it can cause habitual abortion.

metaphyseal fibrous defect 

1. fibrous cortical d.

2. nonossifying fibroma.

neural tube defect  a developmental anomaly of failure of closure of the neural tube, resulting in conditions such as anencephaly or spina bifida.

retention defect  a defect in the power of recalling or remembering names, numbers, or events.

septal defect  a defect in a cardiac septum resulting in an abnormal communication between the opposite chambers of the heart.

ventricular septal defect  a congenital cardiac anomaly in which there is persistent patency of the ventricular septum in either the muscular or fibrous portions, most often due to failure of the bulbar septum to completely close the interventricular foramen.

Abnormal communication between the ventricles in ventricular septal defect.

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ventricular septal defect

n. Abbr. VSD

A congenital defect in the septum between the cardiac ventricles, usually resulting from failure of the spiral septum to close the interventricular foramen.

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ventricular septal defect (VSD),

the most common congenital cardiac anomaly, characterized by one or more abnormal openings in the septum separating the ventricles. The openings, which may range in size from 1 to 2 mm to several centimeters, permit oxygenated blood to flow from the left to the right ventricle and to recirculate through the pulmonary artery and lungs. Small defects may close spontaneously, and children with such defects are usually asymptomatic. Large defects may lead to bacterial endocarditis, lower respiratory tract infections, pulmonary vascular obstructive disease, aortic regurgitation, or congestive heart failure. Children with large defects may show rapid breathing, poor weight gain, restlessness, and irritability. Diagnosis is established by echocardiography and cardiac catheterization. Treatment consists of surgical repair of the defect, preferably in early childhood. In certain cases, the defect may be closed via a percutaneous approach.

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ventricular septal defect (VSD),

n an abnormal opening in the septum separating the ventricles of the heart. It is the most common congenital heart defect. Children with small defects are usually without symptoms. Large defects can prevent proper oxygenation of the blood and may initiate congestive heart failure, if not surgically corrected.

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ventricular

pertaining to a ventricle.

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ventricular assist device

a circulatory support device consisting of a pump with afferent and efferent conduits attached to the left ventricular apex and the ascending aorta, respectively, each conduit containing a porcine valve to ensure unidirectional blood flow; the pump rests on the external chest wall and is connected to an external pneumatic power source and control circuit.

ventricular asystole

see asystole.

ventricular bands

folds of mucosa, parallel and craniolateral to the vocal cords. Called also false vocal cords, vestibular folds.

double right ventricular outlet

a cardiac anomaly rarely seen in animals in which both the aorta and pulmonary artery arise from the right ventricle and there is a defect in the ventricular septum.

excessive ventricular moderator bands

a rare syndrome of cardiomyopathy in cats caused by an excessive number of moderator bands in the left ventricle, extending from the papillary muscles to the ventricular septum.

ventricular extrasystoles

see ventricular extrasystole.

ventricular fibrillation

see ventricular fibrillation.

ventricular function curve

see starling curves.

ventricular hypertrophy

see ventricular hypertrophy.

ventricular outflow obstruction

flow of blood from the ventricles is impaired by lesions or congenital abnormalities in the outflow tract. This is usually associated with hypertrophy of the ventricle and can be demonstrated with echocardiography or contract radiography. Left outflow obstruction occurs with stenosis and other anomalies of the aorta; right outflow obstruction occurs with pulmonic stenosis, pulmonic insufficiency, tetralogy of Fallot, and double-chambered right ventricle.

ventricular premature contraction (VPC)

see premature heartbeats.

ventricular rupture

due to focal weakness causes sudden death due to cardiac tamponade.

ventricular septal defect

a congenital heart defect in which there is persistent patency of the ventricular septum in either the muscular or fibrous portion most often due to failure of the bulbar septum to completely close the interventricular foramen. The defect permits flow of blood directly from one ventricle to the other, bypassing the pulmonary circulation and producing varying degrees of cyanosis because of oxygen deficiency. Its clinical characteristics also include a systolic murmur and a palpable thrill on both sides of the chest, dyspnea and poor exercise tolerance. The occurrence is sporadic except that it is inherited in goats and dogs.

ventricular septum

the muscular wall between the ventricles. A small section, between the aortic vestibule and the right atrium, is membranous. Failure of the septum to close completely during fetal growth causes a septal or subaortic defect.

ventricular shortening fraction

in echocardiography, the percentage change in diameter from diastole to systole. Calculated from the internal systolic and diastolic dimensions. It is a measure of mycocardial function.

ventricular slice method

a method for examination of fixed heart by cutting it into 0.5 inch thick slices, perpendicular to the plane of the ventricular septum, from apex to base. Useful in examination of myocardial lesions and cardiomyopathy.

ventricular tachycardia

is manifested by a high heart rate with or without arrhythmia. In both cases there is severe cardiac disease and often acute heart failure.

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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 Left → Right 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 Left → Right 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