B.38 Atrial and Ventricular Septal Defects

Question 1

B.38 Atrial and Ventricular Septal Defects
Epidemiology:

ASD

Answer 1

Second most common congenital heart defect (CHD) (± 2,100 live births).
Females are more affected than males

Question 2

B.38 Atrial and Ventricular Septal Defects
Etiology:

ASD

Answer 2

Down Syndrome
Fetal Alcohol Syndrome
Holt-Oram Syndrome
Associated with atrial septal defect (ASD)
Adventitious Defects
Affects approximately 1 in 1,000 children.

Question 3

B.38 Atrial and Ventricular Septal Defects
Pathophysiology:

ASD

Answer 3

Increased pulmonary blood flow or excessive resorption of the atrial septum occurs in utero leading to atrial septal defects.

Ostium Primum Atrial Septal Defect (ASD I): 15% - 20% (usually isolated).

Ostium Secundum Atrial Septal Defect (ASD II): 70% - 80% (commonly associated with other heart defects).

Sinus Venosus Defect:
Generally a low-pressure shunt, allowing blood flow from the left atrium to the right atrium.
Patients may be asymptomatic.

Question 4

B.38 Atrial and Ventricular Septal Defects
Associated Conditions:

ASD

Answer 4

Oxygenated blood shunting from the left atrium (LA) to the right atrium (RA) causes increased oxygen saturation in the RV and pulmonary artery (PA).
May lead to supraventricular arrhythmias, pulmonary hypertension, and/or Eisenmenger syndrome.

Question 5

B.38 Atrial and Ventricular Septal Defects
Clinical Features

ASD

Answer 5

Dependence on Defect Size and Shunt Volume:
Often symptomless for small defects.
Moderate to large defects may present symptoms.

Symptoms:
Can vary depending on heart failure severity.
Atrial septal defects (ASDs) usually become evident with advancing age.

Question 6

B.38 Atrial and Ventricular Septal Defects
Physical Examination Findings:

ASD

Answer 6

Systolic ejection click from the second left intercostal space (ICS) due to pulmonary artery stenosis.
A widely split second heart sound (S2) over the second left ICS, which may be fixed (not affected by respiration).
Soft mid-systolic murmur at the lower left sternal border due to blood flow through the tricuspid valve.

Question 7

B.38 Atrial and Ventricular Septal Defects
Diagnostics

ASD

Answer 7

Echocardiography (confirmatory test):
Visualizes the atrioventricular communication in the standard four-chamber and subcostal views.
Electrocardiogram (ECG):
Signs of right ventricular hypertrophy (RVH), possible right axis deviation, PR prolongation, or incomplete right bundle branch block (RBBB).

Chest X-ray findings:
- Enlarged right atrium, ventricle, and pulmonary artery.
- Enhanced pulmonary vasculature.

Question 8

B.38 Atrial and Ventricular Septal Defects
Treatment:

ASD

Answer 8

Spontaneous Closure:
In some children with atrial septal defects (ASD), spontaneous closure may happen.

Patch Repair:
Recommended for symptomatic patients with a significant left-to-right shunt.
May involve surgical intervention or a percutaneous transcatheter procedure.

Question 9

B.38 Atrial and Ventricular Septal Defects
Complications:

ASD

Answer 9

Paradoxical Embolism:
This condition, which can lead to ischemic stroke, occurs when small blood clots from the inferior vena cava bypass the pulmonary circulation.
These clots can directly enter the left atrium, resulting in paradoxical embolism and stroke, particularly in cases of thromboembolism.

Heart Failure:
Heart failure may develop as a complication.

Question 10

B.38 Atrial and Ventricular Septal Defects
Epidemiology:

VSD

Answer 10

Prevalence:
VSD (ventricular septal defect) is the most common congenital heart defect, occurring in approximately 4 out of every 1,000 live births.
It can present as an isolated defect or in combination with other conditions, such as atrioventricular septal defects (AVSD), tetralogy of Fallot, or transposition of the great arteries (TGA).

Question 11

B.38 Atrial and Ventricular Septal Defects
Etiology:

VSD

Answer 11

Genetic Syndromes:
Frequently associated with conditions such as Down syndrome, Edward syndrome, and Patau syndrome.
Can also result from intrauterine infections (e.g., TORCH).

Maternal Risk Factors:
Include diabetes, obesity, and systemic hypertension.

Question 12

B.38 Atrial and Ventricular Septal Defects
Pathophysiology:

VSD

Answer 12

Defects are primarily found in the membranous part of the ventricular septum.

Impact on Ventricular Function:
Defects in the ventricular septum lead to ventricular overload, causing the following effects:
Right ventricular (RV) volume overload, resulting in RV eccentric hypertrophy.
Elevated pulmonary blood flow, which increases pulmonary artery pressure.
Left ventricular (LV) eccentric hypertrophy due to increased cardiac output.
Decreased oxygen saturation in the right ventricle and pulmonary artery.

Question 13

B.38 Atrial and Ventricular Septal Defects
Clinical Features

VSD

Answer 13

Small Defects:
Typically asymptomatic.
Medium-Sized or Large Defects:
Can cause heart failure, often noticeable by around 2–3 months of age.
Symptoms may emerge after initial pulmonary vascular resistance (PVR) decreases at birth, potentially leading to:
Increased PVR resulting in right ventricular pressure overload and associated symptoms.

Physical Examination Findings:
Hyperdynamic precordium may be observed in cases with hemodynamic significance.
Harsh Holosystolic Murmur:
Most pronounced at the tricuspid area.
Larger VSDs generally produce a louder heart sound (S2) compared to smaller ones.
Increased intensity may indicate an overload situation if pulmonary hypertension develops.

Question 14

B.38 Atrial and Ventricular Septal Defects
Diagnostics

VSD

Answer 14

Echocardiography (Confirmatory Test):
Used to evaluate the defect and assess the left-to-right shunt.
Doppler ultrasound helps identify significant ventricular overload.

ECG:
Generally shows normal findings.
For medium-sized or large defects:
Signs may include left ventricular hypertrophy (LVH) due to volume loading, indicated by:
QRS amplitude changes and left axis deviation.
Signs of right ventricular hypertrophy (RVH) due to pulmonary overcirculation, including axis deviation, P wave prolongation, or incomplete right bundle branch block (RBBB).

Chest X-ray:
May reveal:
Left atrial and ventricular enlargement.
Changes in the size of the pulmonary artery due to increased pulmonary blood flow.

Question 15

B.38 Atrial and Ventricular Septal Defects
Treatment:

VSD

Answer 15

Small Defects:
Often close spontaneously and may require only routine follow-up.

Medium-Sized and Large Defects:
Surgical intervention is generally advised, especially in cases where symptoms are present.

Surgical Options:
In children under 1 year old who show signs of volume overload and have not yet received medical management.
Closure of a VSD may be necessary to normalize left and right heart pressures, as well as to prevent long-term complications.

If Eisenmenger Syndrome Develops:
Heart-lung transplant or lung transplant with concurrent VSD repair may be indicated.

Question 16

B.38 Atrial and Ventricular Septal Defects
Complications:

Answer 16

• Arrhythmias
• Heart Failure
• Eisenmenger Syndrome
• Infective Endocarditis
• Aortic Regurgitation