Congenital Heart Disease Chd Biology Essay

Published: Last Edited:

This essay has been submitted by a student. This is not an example of the work written by our professional essay writers.

Congenital heart disease is defined as an abnormality in cardiac structure or function that is present at birth, or at times discovered much later.1, 2, 3 .The incidence of moderate to severe structural congenital heart disease is 6 to 8 per 1000 live births. 4,5-6'.This incidence had remained fairly constant over the years in different parts of the world .But in recent years there has been an increase in its incidence which may be due to the inclusion of more trivial forms of congenital heart disease, such as tiny ventricular septal defects that are detected more frequently by the use of highly sensitive echocardiography.7,8,9,10,11

CHD have a wide spectrum of severity in infants. About 2-3 / 1000 newborns will be symptomatic with heart disease in the first year of life. In 40-50% of cases the diagnosis would be established by one week and in the remaining 50-60% by one month of age. With improved diagnostic modalities and advances in both palliative and corrective surgery in the last two decades, the number of children diagnosed with congenital heart disease surviving to adulthood has increased dramatically.12

The timing of presentation and accompanying symptomatology may vary widely and depends on the nature and severity of the anatomic defect, the in utero effects of the structural lesions, and the alterations in cardiovascular physiology secondary to the effects of the transitional circulation.13. Signs and symptoms of heart disease in the newborn period can be variable ranging from hurried breathing, poor feeding, irritability, cyanosis, congestive heart failure, and cardiogenic shock. Rarely a baby with CHD may even be totally asymptomatic.

The presence of certain risk factors can influence the type of presentation eg; Exposure to teratogens can lead to both CHD and extra cardiac manifestations.

Recognition of congenital heart disease in the newborn period is important as CHDs like HLHS, COA, TGA, TAPVC have significant mortality and morbidity in newborn period itself. These babies need to be managed on an emergency basis with medical/palliative and surgical interventions to increase their longevity.

Aims and Objectives


To determine the incidence of Congenital Heart Disease (CHD) among intramural live born neonates.


To study the clinical presentation of the neonates with CHD

To establish the relation between the symptoms /signs suggestive of CHD with echocardiographic finding

To identify the common extra cardiac manifestations associated with CHD

To evaluate the influence of echo cardio graphic examination in the clinical management of the sick neonate suspected to have CHD

Review of Literature

Studies done in the last three decades indicate that the incidence of Congenital Heart Disease is increasing steadily. In 1968, Hoffmann found the incidence to be only 4-5 per 1000 live births2. But, the same author in his recent study, report the incidence to be 12-14 per 1000 live births.4,6 and other recent studies showing higher incidence up to 30|1000 live births.8.10.11

Bernstein et al found the relative frequency of major congenital heart diseases, among live births to be as follows 12

Lesions % of all lesions

Ventricular septal defect 25-30

Atrial septal defect (Secundum) 6-8

Patent ductus arteriosus 6-8

Coarctation of aorta 5-7

Tetrology of Fallot 5-7

Pulmonary valve stenosis 5-7

Aortic valve stenosis 4-7

d- Transposition of great arteries 3-5

Hypoplastic left ventricle 1-3

Hypoplastic right ventricle 1-3

Truncus arteriosus 1-2

Total anomalous pulmonary venous return 1-2

Tricuspid atresia 1-2

Single ventricle 1-2

Double outlet right ventricle 1-2

Others 5-10

The burden of congenital heart disease in India is found to be enormous. As of now, there is no community-based data for the incidence of CHD at birth in India. Among the various hospital based studies conducted in India, the prevalence varies between 2.25 to 26.4/1000 live births3,5,15,16, the more recent ones showing a higher prevalence. This is perhaps due to increasing awareness among pediatricians who are the primary health care providers. This trend may also be related to the wide availability of trained personnel and Echocardiography machines which forms the main stay of diagnosis of CHD in neonates. 3.

The profile of CHD varies depending upon the age group screened. Simple and potentially correctable heart defects, like ventricular septal defect, patent ductus arteriosus and atrial septal defect, are common at all age groups. 3. After studying 574 neonates, Sharma et al found VSD to be the most common Acyanotic CHD (35%), followed by PDA with 28%, and ASD 25%; in the cyanotic group, TGA was seen in one fifth of neonates with CHD and pulmonary atresia and its variants are seen in about 13% of cases.17

Even though the defect is present at birth, the age of appearance of the clinical features vary; this is because, although the most significant transitions in circulation occur in the immediate perinatal period, the circulation continues to undergo changes even after birth, and these later changes may have a hemodynamic impact on cardiac lesions. Also, the fall in pulmonary vascular resistance over the first several weeks of life, facilitates left to right shunting through intra cardiac defects which makes the symptoms more apparent. For example, in patients with a ventricular septal defect, heart failure is often manifested between one to 3 months of age.

The clinical profile of the CHDs could change as the child grows older; some ASD and VSDs may become smaller and even close as the child grows. Alternatively, valvular defects such as stenosis of the aortic or pulmonary valve, which were mild in the newborn period, would become worse if valve orifice growth does not keep pace with patient's growth 12

Depending upon the severity, CHD presenting at birth can be categorized into 3 groups - mild, moderate and severe categories. Severe CHD includes all cyanotic lesions and some acyanotic lesions (Large VSD, Large PDA, Critical AS, Critical PS & Critical Coarctation), which require intervention early in life. Moderate CHD (Mild-Moderate AS or PS, Non-critical Coarctation, Large ASD) are those that require expert care, but less intensive compared to severe CHD. Mild CHD (Small VSD, PDA, ASD, Mild AS or PS) are asymptomatic and often undergo spontaneous resolution 6

The risk of CHD in an offspring is 6% if mother has CHD and the risk is 3% if father has CHD,similarly when one child is affected the risk is 3 % for the sibling.18.19


The etiology of CHD is complex, and in most cases multifactorial. There are a number of recognized associations like Chromosomal abnormalities (Down, Edward, Patau, Turner, cri-du-chat) Contiguous gene syndromes (William's, Di-George's), Single gene defects (Noonan's, Marfan's, isomerism) and Teratogenic drugs (anticonvulsants, alcohol, lithium). 12.14

2- 4 % of cases of congenital heart disease are associated with known environmental or adverse maternal conditions like congenital infection (rubella) and teratogenic drugs (anticonvulsants, lithium) 20



Approximate Incidence/ Mode of Inheritance

Cardiac Features


Trisomy 13


>80% have CHD, VSD most common

Trisomy 18


>95% have CHD, VSD most common.

Trisomy 21


40-50% have CHD, CAVC, VSD most common, also TOF, ASD, PDA

Turner's syndrome


25-45% have CHD. COA, biscuspid aortic valve most common.


Noonan syndrome


>50% have CHD, usually pulmonary valvular stenosis, ASD, hypertrophic CM

Holt- Oram syndrome


>50% have CHD, ASD or VSD

Ellis-van Creveld syndrome


50% have CHD, ASD, Common atrium

Alagille syndrome


Cardiac findings in 90%, PS common.


Williams syndrome

deletion 7q11

50-70% have CHD, supravalvar aortic Stenosis

DiGeorge syndrome

deletion 22q11

Interrupted aortic arch, Conotrunchal malformations, TOF.



50% have CHD, VSD most common


50-70% have CHD, Conotrunchal defects

The neonate with congenital Heart Disease

An infant with cardiac disorder may present during the neonatal period in myriad ways. They can present with a constellation of symptoms ranging from breathlessness, tachycardia, bradycardia, significant murmur, poorfeeding hepatomegaly or with a murmur with out symptoms.. As most of these symptoms are common to many neonatal illnesses like Sepsis, RDS, Pneumonia, making a clinical diagnosis based on these symptoms alone might be difficult. Also, it is true that not all CHDs presenting in the neonatal period will have a significant murmur; so unless one has a high index of suspicion and asks for necessary investigations the diagnosis may be easily missed out. But, the presence of an abnormal facies or a syndrome like trisomies, might give a clue for a possibility of CHD.

. Any infant noted to have multiple system involvement should be followed up closely for any evidence of congenital heart disease.

3.2.1 Age of presentation of common CHD: 22

Congenital heart disease TGA,Hypoplastic left heart syndrome, Aortic stenosis,Tricuspid tresia,coarcation of aorta can present at birth while PDA,Common AVdefect manifestation around one week, Pulmonary stenosis,usually present around one month while TOFaround one year. ASD can present as late as 5 years

3.2.2. Congenital heart lesions presenting with shock:

Hypoplastic left heart syndrome, Interrupted aortic arch, Coarctation of aorta can present in the first week of life while myocardial disease, arrhythmias can present at any age with shock.

3.2.3. Congenital heart lesions presenting with asymptomatic murmur:

Congenital heart disease like Aortic stenosis, Pulmonary stenosis present in first two days of life while VSD, PDA (small) may present after 3days, ASD present usually after 3months ,innocent murmurs can present at any age.




Hurried breathing

Excessive forehead sweating

Difficulty / poor feeding

Decreased urine output

Convulsions, neurological deficits

Not gaining weight

Irritability, restlessness

B) Signs

Signs of CHD include Tachypnea, Tachycardia (congestive cardiac failure), Bradycardia (heart block) Abnormal s2 -A widely split and fixed S2 as seen in ASD, PS, RBBB,. A narrowly split S2 is found in conditions in which the pulmonary valve closes early (e.g., pulmonary hypertension) or the aortic valve closure is delayed (e.g., AS). This is occasionally found in a normal child. The presence of Systolic murmur grade II or more Diastolic murmer of (any Grade) Cardiomegaly, Hepatomegaly ,Abnormal blood pressure may also indicate the possibility of finding a structural heart disease.


Criteria to Diagnose CHD -Decide Presence or Absence of Heart Disease by NADA'S Criteria: 23

Major criteria Minor criteria

Systolic murmur of > grade III Systolic murmur of < gradeIII

Diastolic murmur Abnormal x-ray

Congestive heart failure Abnormal ECG

Cyanosis Abnormal S2

Abnormal blood pressure

Presence of one major or two minor criteria are essential for diagnosis of heart disease.

Investigations in Neonates with Congenital Heart Disease 24

3.5.1 Electrocardiogram

Normal ranges of QRS axis vary with age. Newborns normally have RAD compared with the adult standard. Normal axis of 180° is noted in newborns (+30 to +180°). Although, in many of the CHDs, ECG may not be greatly helpful, at least certain changes are diagnostic. For example, in a cyanotic infant, left axis deviation with left ventricular hypertrophy should lead one to suspect tricuspid atresia unless proven otherwise. Rightward axis with left ventricular hypertrophy and right atrial enlargement might indicate pulmonary valve atresia/ critical pulmonic stenosis with hypoplastic right ventricle. Right axis deviation with severe right ventricular hypertrophy with very poor left ventricular voltage may mean hypoplastic left ventricle. Likewise, presence of ventricular pre-excitation of type-B in a cyanotic infant with enlarged heart might lead one to suspect Ebstein's malformation of tricuspid valve.

3.5.2.Chest roentgenography

In many of the heart diseases, the ongoing hemodynamic changes could result in cardiomegaly; but, there are few exceptions. Heart is enlarged only if the cardiothoracic ratio is greater than 0.6 on the posterior-anterior view in infants. In some of the CHDs the shape of the heart may be typical. A "boot-shaped" heart with decreased pulmonary blood flow is typical in infants with cyanotic tetralogy of Fallot (TOF), and rarely, in some infants with tricuspid atresia too. While a narrow-waisted and "egg-shaped" heart with increased pulmonary blood flow in a cyanotic infant strongly suggests transposition of the great arteries (TGA), the "snowman" sign with increased pulmonary blood flow is typical of supracardiac type of total anomalous pulmonary venous return (TAPVR); the left vertical vein, left innominate vein, and dilated SVC make up the snowman's head

3.5.3. 2 D Echocardiography

Echocardiography (echo) is a safe, noninvasive test for the diagnosis of CHD.Echo studies which use ultrasound, provide anatomic diagnosis as well as functional information. Echo reduces the requirement for invasive studies such as cardiac catheterization. The echo examination can be used to evaluate cardiac structure in congenital heart lesions, estimate intracardiac pressures and gradients across stenotic valves and vessels, quantitate cardiac contractile function (both systolic and diastolic), determine the direction of flow across a defect, examine the integrity of the coronary arteries, and detect the presence of vegetations from endocarditis, as well as the presence of pericardial fluid, cardiac tumors, and chamber thrombi. Echocardiography may also be used to assist in the performance of pericardiocentesis, balloon atrial septostomy and endocardial biopsy and in the placement of flow-directed pulmonary artery (Swan-Ganz) monitoring catheters. A complete echocardiographic examination usually entails a combination of M-mode and two-dimensional imaging, as well as pulsed, continuous, and color Doppler flow studies.


M-mode echocardiography displays a one-dimensional slice of cardiac structure varying over time. It is used mostly for the measurement of cardiac dimensions (wall thickness and chamber size) and cardiac function (fractional shortening, wall thickening).


Doppler echocardiography displays blood flow in cardiac chambers and vascular channels based on the change in frequency imparted to a sound wave by the movement of erythrocytes


Diagnostic catheterization is helpful to (1) to assist in the initial diagnosis of some complex congenital heart lesions (tetralogy of Fallot with pulmonary atresia and major aortopulmonary collateral arteries [MAPCAs], pulmonary atresia with intact ventricular septum and coronary sinusoids); (2) in cases in which other imaging studies are equivocal; (3) in patients for whom hemodynamic assessment is critical (to determine the size of a left-to-right shunt in borderline cases, or to determine the presence or absence of pulmonary vascular disease in a patient with a left-to-right shunt); (4) between stages of repair of complex congenital heart disease (hypoplastic left heart syndrome).


The miniaturization of catheter delivery systems has allowed for the safe application of many of these interventional catheterization techniques, even in neonates and premature infants.

Figure : Graph

Subjects and Methods

The present study was conducted in a tertiary care neonatal centre between August 2011 to July 2012.During this study period all neonates who were born in the hospital suspected to have congenital heart disease formed the subjects. They were followed up up to the time of discharge from nursery.


All Intramural live born babies with clinical suspicion of congenital heart disease


Out born neonates

STUDY DESIGN: Prospective observational study

Brief explanation of the Procedure

Babies suspected to have CHD were included in the study .Informed consent was taken from parents of babies who were suspected to have CHD,the nature of the study, purpose and procedure was explained to parents in detail in their own language and also was given in a printed information sheet.

A clinical suspicion of CHD was entertained when babies presented with the following clinical symptoms of CHD like Cyanosis ,Hurried breathing, Excessive forehead sweating, Difficulty| poor feeding, Decreased urine output, Convulsions, neurological deficits, Irritability, restlessness, and signs of CHD like Tachypnea ,Tachycardia Bradycardia, Abnormal S2, Murmur-Systolic murmur >grade III/diastolic murmur(any grade),and Hepatomegaly,.Those neonates who were suspected to have CHD underwent thorough general physical examination, head to foot examination for extra cardiac manifestations and also a detailed systemic examination was done Their family history and risk factors for development of CHD were reviewed. Blood pressure was measured in all four limbs using noninvasive blood pressure (NIBP) measuring method.SpO2 was measured using Pulse Oximeter .Chest x-ray and ECG were taken initially and later an ECHO was done to confirm the diagnosis .ABG was done in needed cases. The nature of treatment given was noted down and these babies were followed up until discharged from NICCU.

Study Design

Data Collection

A proforma was used to obtain information.The purpose of the study was explained to parents and data was collected after taking informed consent

Statistical Methods

The collected data was compiled and analyzed using MS.exel and SPSS.version 16 soft ware.Tables were generated to demonstrate the findings.Students t test, and percentage Analysis was done to find p value.