Chapter 25: Alterations of Cardiovascular Function in Children

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Questions and Answers

What is the primary time frame during which most congenital heart diseases begin to develop?

At birth

First trimester

Eighth week of gestation (correct)

Second trimester

Which of the following is NOT listed as an environmental risk factor associated with congenital heart disease?

Diabetes mellitus

Intrauterine viral infections

Advanced maternal age

Genetic mutations (correct)

Cyanosis in congenital heart defects typically indicates what issue?

Normal blood circulation

Increased oxygen supply to tissues

Excessive blood flow through lungs

Insufficient oxygenated blood reaching tissues (correct)

What does the classification of a congenital heart defect NOT consider?

Presence of arrhythmias Signup and view all the answers

Acyanotic heart defects that increase pulmonary blood flow primarily result in which type of blood shunting?

Left-to-right shunt Signup and view all the answers

Which condition is associated with a higher incidence of congenital heart disease due to advanced maternal age?

Down syndrome Signup and view all the answers

What does a left-to-right shunt in congenital heart defects NOT cause?

Cyanosis in the systemic circulation Signup and view all the answers

Which of the following directly affects the direction of blood flow in congenital heart defects?

Differences in pressure and resistance Signup and view all the answers

Which congenital heart defect is characterized by a direct communication between the two circulatory systems?

Atrial septal defect Signup and view all the answers

What condition is often caused by excess blood flow into the pulmonary circulation?

Pulmonary overcirculation Signup and view all the answers

What is a common consequence of a large abnormal communication between left and right heart circuits?

Decreased oxygen saturation in systemic circulation Signup and view all the answers

How does compensatory ventricular hypertrophy occur in cases of less severe obstruction?

As a response to increased afterload Signup and view all the answers

In cyanotic congenital heart defects that decrease pulmonary blood flow, what primarily causes cyanosis?

Inadequate volume of oxygenated blood Signup and view all the answers

Which congenital heart defect is associated with significant risk of left ventricular failure due to volume and pressure overload?

Total anomalous pulmonary venous connection Signup and view all the answers

What distinguishes systemic hypertension in children from that in adults?

Secondary hypertension is more common in children Signup and view all the answers

What is a unique clinical manifestation of heart failure in children?

Failure to thrive Signup and view all the answers

What initial treatment strategies for congenital heart defects focus on?

Eliminating existing symptoms and cyanosis Signup and view all the answers

Which condition can develop from untreated Kawasaki disease?

Coronary artery aneurysms Signup and view all the answers

What is a known cause of obstruction in the left ventricular outflow tract?

Aortic stenosis Signup and view all the answers

In Which congenital defect does a right-to-left shunt occur due to decreased pulmonary blood flow?

Tetralogy of Fallot Signup and view all the answers

Study Notes

Congenital Heart Disease

Most congenital heart defects (CHD) develop by the eighth week of gestation.
Environmental risk factors for CHD include maternal conditions like intrauterine viral infections, diabetes, medications, complications of advanced maternal age, antepartal bleeding, and prematurity.
Genetic risk factors for CHD include Down syndrome, trisomies 13 and 18, cri du chat syndrome, and Turner's syndrome.
CHD classification is based on:
- Whether the defect causes cyanosis
- Whether the defect causes increased or decreased pulmonary blood flow
- Whether the defect causes ventricular outflow obstruction
Cyanosis, a bluish discoloration of the skin, indicates inadequate oxygenated blood delivery to tissues.
Cyanosis can be caused by defects that:
- Restrict pulmonary blood flow
- Overload the pulmonary circulation, leading to pulmonary edema and respiratory distress
- Cause a large right-to-left shunt of deoxygenated blood
Congenital heart defects with direct communication between the pulmonary and systemic circulations allow blood to shunt between systems, mixing oxygenated and deoxygenated blood.
The direction of shunting depends on pressure and resistance differences between the two systems, with flow moving from high pressure to low pressure.
Acyanotic heart defects increasing pulmonary blood flow involve abnormal openings:
- Atrial septal defect
- Ventricular septal defect
- Patent ductus arteriosus
- Atrioventricular canal defect
- These allow blood to shunt from the left (systemic circulation) to the right (pulmonary circulation) without causing cyanosis.
Ventricular outflow obstruction is common in:
- Aortic stenosis (left ventricle)
- Pulmonary stenosis (right ventricle)
Mild obstruction can be compensated for by ventricular hypertrophy and collateral circulation development.
Large left-to-right shunts can lead to pulmonary circulation overload, causing left ventricular failure.
Cyanotic congenital defects involving mixing of oxygenated and deoxygenated blood in the heart or great arteries include:
- Tetralogy of Fallot (TOF)
- Transposition of the great arteries
- Total anomalous pulmonary venous connection
- Truncus arteriosus
- Hypoplastic left heart syndrome
In cyanotic defects decreasing pulmonary blood flow (TOF), myocardial hypertrophy cannot compensate for restricted right ventricular outflow.
This reduces lung blood flow and causes cyanosis due to insufficient oxygenated blood and a right-to-left shunt.
Heart failure (HF) is often caused by congenital heart defects increasing pulmonary blood volume.
Children with HF may experience failure to thrive, a unique symptom.
Treatment for CHD focuses on:
- Controlling HF symptoms or cyanosis
- Interventional procedures in the cardiac catheterization lab
- Surgical palliation or repair to establish pulmonary blood flow or restore normal circulation

Acquired Cardiovascular Disorders

Acquired heart disease in children includes:
- Kawasaki disease (KD)
- Systemic hypertension
KD is an acute systemic vasculitis that can lead to coronary artery aneurysms and thrombosis if untreated.
Systemic hypertension in children differs from adult hypertension in its etiology and presentation.
In children with significant hypertension, secondary hypertension should be evaluated, often due to kidney disease or coarctation of the aorta (COA).

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