This document summarizes congenital heart disease, noting that ventricular septal defects (VSDs) are the most common type. Causes are often multifactorial and developmental. Clinical features include left-to-right or right-to-left shunts, or obstruction. Common defects causing left-to-right shunts are VSDs, atrial septal defects (ASDs), and patent ductus arteriosus. Tetralogy of Fallot is the most common cyanotic congenital heart disease and involves pulmonary stenosis, ventricular hypertrophy, a VSD, and an overriding aorta. Transposition of the great arteries is also discussed.

1. Heart - Pathology
Congenital Heart Disease
 MC type of heart disease among children
 MC type= VSD
 Etiology and Pathogenesis
 Multifactorial = majority of cases
 Developmental
 Trisomy 21 (Down syndrome)
 MC known genetic cause
 Endocardial cushion defects (AVSD) & ASD
Di -George syndrome with TOF
 Environment= infection (congenital rubella) or teratogens
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Dr. Krishna Tadepalli, MD, www.mletips.com

2. Heart - Pathology
Congenital Heart Disease
 Clinical Features
 Malformations causing
left-to-right shunt
right-to-left shunt
Obstruction
 Mechanisms - left-to-right shunt
Type of Defect
Mechanism
Ventricular Septal Defect
(VSD)
hole within the membranous or muscular portions
of the interventricular septum
Atrial Septal Defect (ASD)
A hole from a septum secundum or septum
primum defect in the interatrial septum
Patent Ductus Arteriosus
(PDA)
Ductus Arteriosus remains open (normally closes
Soon after birth)
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Dr. Krishna Tadepalli, MD, www.mletips.com

3. Heart - Pathology
Congenital Heart Disease
 Mechanisms - right-to-left shunt
Tetrology of Fallot
Pulmonic stenosis  right ventricular
hypertrophy , VSD& overriding aorta
Transposition of Great
Vessels
Aorta arises from the right ventricle and the
pulmonic trunk from the left ventricle. A VSD, or
ASD with PDA, is needed for survival
Truncus Arteriosus
Incomplete separation of the aortic and
pulmonary outflows
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Dr. Krishna Tadepalli, MD, www.mletips.com

4. Heart - Pathology
Congenital Heart Disease
 Mechanisms - others
Hypoplastic Left Heart
Syndrome
hypoplasia or atresia of the aortic and mitral valves, with
a small to absent left ventricle
Coarctation of Aorta
outflow obstructive narrowing of the aortic lumen,
proximal (infantile form) or distal (adult form) to the
ductus
Total Anomalous
Pulmonary Venous Return
(TAPVR)
pulmonary veins drain into left innominate vein,
coronary sinus, or some other site
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Dr. Krishna Tadepalli, MD, www.mletips.com

5. Heart - Pathology
Congenital Heart Disease
 Left-to-right shunts
 ASD, VSD, and Patent Ductus Arteriosus [PDA]
 Congenitally acyanotic
 Late cyanotic congenital heart disease or Eisenmenger syndrome
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ASD
MC congenital cardiac anomaly asymptomatic until adulthood
Secundum ASD =90% of all ASDs
 Defect is due to deficient or fenestrated oval fossa
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Volume hypertrophy of RA & RV
Pulmonary blood flow - 2 to 4 times normal
Murmur at pulmonary area
Complications = uncommon
Normal postoperative survival
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Dr. Krishna Tadepalli, MD, www.mletips.com

6. Heart - Pathology
Congenital Heart Disease
VSD
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Most common congenital cardiac anomaly (42%)
Spontaneously close in half of patients
 ⅔ rd
are associated with other defects (TOF)
 clinically = Size is most critical
 Morphology
 Membranous VSD(90%)
 Swiss-cheese septum =Multiple muscular septum VSDs
 Right ventricular hypertrophy and pulmonary hypertension
are present from birth
 Rx = Surgical closure indicated at age 1 year with large defects
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Dr. Krishna Tadepalli, MD, www.mletips.com

7. Heart - Pathology
Congenital Heart Disease
PDA
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Majority are isolated defects (90%)
Others (10%)-associated with VSD, COA, or PS, AS
No functional difficulties at birth & childhood
Continuous harsh machinery-like murmur
PDA is Life-threatening or life-saving
 prostaglandin E  preservation of ductal patency
 ? Drug closes PDA
AVSD
(endocardial cushion defect )
 Superior & inferior endocardial cushions fail to fuse
 Inadequate formation of the AV valves
 MC with Down syndrome
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Dr. Krishna Tadepalli, MD, www.mletips.com

8. Heart - Pathology
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Congenital Heart Disease
Right to left shunts
Tetralogy of Fallot - MC cyanotic congenital heart disease
Transposition of the great arteries
Tricuspid atresia
Total anomalous pulmonary venous connection
Truncus Arteriosus
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Dr. Krishna Tadepalli, MD, www.mletips.com

9. Heart - Pathology
Tetralogy of Fallot
 Tetra = 4
 sub pulmonary stenosis
 Right ventricular hypertrophy
 VSD
 Aorta that overrides the VSD
 Morphology
 Boot-shaped Heart (due to right ventricular hypertrophy)
 Aortic valve insufficiency or ASD (Pentology)
 Pink Tetralogy = Mild Sub-pulmonary stenosis
TGA
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TGA incompatible unless a shunt exists
TGA + VSD (35%) = stable shunt
TGA + Patent foramen ovale or PDA (65%)=unstable shunts
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Dr. Krishna Tadepalli, MD, www.mletips.com

10. Heart - Pathology
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Truncus Arteriosus
Single great artery that receives blood from both ventricles
Early systemic cyanosis
Irreversible pulmonary HTN
Tricuspid Atresia
High mortality in the first weeks
underdevelopment (hypoplasia) of RV
Congenital Cyanosis
Coarctation of Aora
Males are affected twice
females with Turner syndrome
Two classic forms – infantile, adult
half of cases = associated with bicuspid aortic valve
Clinical features= rib notching, pan systolic murmur & thrill
 hypertension in the upper extremities
 weak pulses and Hypotension in the lower extremities
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Dr. Krishna Tadepalli, MD, www.mletips.com

11. Heart - Pathology
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Dr. Krishna Tadepalli, MD, www.mletips.com