CONGENITAL HEART DISEASE

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Last Updated : 1/18/2012
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N C Joshi
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CLINICAL PRESENTATION
Despite a large number of cardiac defects that exist, there are only a limited number of physiological disturbances that can be produced. Congenital heart disease usually presents in infancy as cyanosis or heart failure or a combination of both, heart murmur, circulatory shock, stridor, hypercyanotic spells, different respiratory tract infections and growth failure.

Cyanosis
Cyanosis is blue discoloration of the skin, mucus membranes and nails due to presence of desaturated hemoglobin more than 5 gm/dl percent in arterial blood. Those cardiac anomalies in which systemic venous return reaches systemic circulation without passage through lungs, presents with central cyanosis and clubbing of fingers.

Cyanosis occurs under following circumstances:
- Reduced pulmonary blood flow in defects with right ventricular outflow tract obstruction
- Right to left shunts as in Tetralogy of Fallot
- Discordant ventriculoarterial connections as in transposition of great arteries, and
- Mixing of venous and arterial blood as in truncus arteriosus or single ventricle.

Heart Failure
When heart cannot supply the blood flow demanded by tissues, a clinical syndrome of symptoms and signs manifest from elevated atrial pressure. It manifests with rapid and labored breathing due to pulmonary edema, pallor with peripheral cyanosis due to poor cardiac output, tachycardia and excessive sweating due to increased sympathetic activity and feeding difficulties.

Heart failure occurs in following situations:
- Volume overload in all defects with left to right shunt like ventricular septal defect, atrial septal defect, patent ductus arteriosus,
- Pressure overload in pulmonary and aortic valve stenosis
- Intrinsic myocardial diseases as in cardiomyopathies, and
- Decreased or increased diastolic fillings as in tachyarrhythmias and bradyarrhythmias.

Heart Murmurs


In older children and in infants, congenital heart disease presents as a heart murmur detected on routine examination. The murmurs are produced due to abnormal pressure gradient across laminar or nonlaminar pathways. The murmur is continuous in patent ductus arteriosus, pansystolic in ventricular septal defect and pulmonary stenosis and diastolic in atrioventricular valve stenosis.

Shock
Cardiac malformations resulting in a hypoplastic ascending aorta, aortic atresia result in low cardiac output. Child appears extremely ill with cold extremities, diminished pulses, low blood pressure, peripheral cyanosis and is semicomatose.

Hypercyanotic Spells
In cardiac malformations with pulmonary infundibular stenosis, the obstruction is of dynamic variety. Whenever the muscular outflow tract contracts, blood flow to pulmonary circuit diminishes and patient gets intense cyanosis. It occurs in Fallot's tetralogy and defects with Fallot's physiology.

Stridor
Malformations leading to compression of trachea and bronchi causing obstruction of the airways, present with stridor, as seen in vascular rings and in dilated pulmonary artery due to increased pulmonary blood flow.

Chest Pain
Malformations like anomalous origin of left coronary artery, severe aortic stenosis lead to myocardial ischemia and patient presents with episodes of screaming, pallor and chest pain.

Recurrent Respiratory Tract Infections
In cardiac defects with left to right shunt, as seen with ventricular septal defect and patent ductus arteriosus, there is a decreased lung compliance which leads to frequent respiratory tract infections.

Growth Failure
Growth failure is a very common manifestation of heart defects due to poor oxygen saturation in the growing tissues, persistent heart failure, and frequent respiratory infections with undernutrition.

Murmurs
- Incidence: 2/3 to 3/4 of all children
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Types of murmurs

: systolic, diastolic and continuous
- Groups of murmurs:
* Functional murmur - secondary to anemia, fever etc.
* Innocent murmur - Still's murmur, venous, hum, etc
* Organic murmur - secondary to cardiovascular defect function


Auscultation


CYANOSIS

Causes of cyanosis

with excessive pulmonary blood flow:
- Transposition of great arteries
- Total anomalous pulmonary venous return
- Hypoplastic left heart syndrome
- Truncus arteriosus
Causes of Cyanosis with Inadequate Pulmonary Blood flow
- Pulmonary atresia or severe stenosis with
- Ventricular septal defect
- Intact ventricular septum
- Tricuspid atresia or stenosis
- Tricuspid insufficiency

CONGESTIVE HEART FAILURE
Causes of CCF in 1st week of life:
Cardiac causes:
- Hypoplastic left heart syndrome
- Coarctation of aorta
- D-transposition of great arteries
- Myocarditis
Extracardiac causes:
- A-V malformation
- Anemia
- Polycythemia
- Infant of diabetic mother

Causes of CCF after 1st week of life
In a 2 month old:
- D-transposition of great arteries
Between 2 months to 6 months of age:
- Ventricular septal defect
- Patent ductus arteriosus
- Endocardial cushion defect
- Endocardial fibroelastosis
- Anomalous left coronary artery
- Left ventricle obstruction
Between 6 months to 1 year of age:
- Endocardial fibroelastosis
- Ventricular septal defect
Between 1 year to 15 years of age:
- Myocarditis
- Rheumatic fever
- Subacute bacterial endocarditis
- Acute glomerulonephritis

References

Contributor Information and Disclosures N C Joshi
Consultant Pediatrician and Pediatric Cardiologist, Nanavati Hospital, Mumbai, India


First Created : 1/16/2001
References
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