Congenital Heart Disease Echocardiographic Evaluation Study Notes

Interatrial Communications

• Described from the right atrial perspective.
• Types:
  • Secundum ASD: Most common.
  • Sinus venosus ASDs: Occur where the superior vena cava (SVC) or inferior vena cava (IVC) inserts.
  • Primum defects: Endocardial cushion defect abnormality.
  • Unroofed coronary sinus: Least common.

True Atrial Septal Defects

• Patent Foramen Ovale (PFO).
• Secundum Atrial Septal Defects:
  • Defect in the oval fossa tissue.
  • Pathology: Hole in the fossa ovalis or multiple small fenestrations.
  • Evaluation: Transesophageal Echo (TEE) useful for characterization due to implications for percutaneous closure.

Secundum ASD Evaluation

• Transthoracic Imaging:
  • Apical four-chamber view (modified).
  • Subcostal view.
  • Color flow demonstrates left-to-right shunt and right heart dilation.
  • Limitations: Challenging to characterize size and location, thus TEE is helpful.
• Transesophageal Echo (TEE):
  • 120-degree view: Right atrium (RA) and left atrium (LA) with defect in the atrial septum.
  • Color flow confirms left-to-right shunt.

Rims of Secundum ASD

• Importance: Determines suitability for percutaneous closure.
• Six Rims:
  • Superior vena cava (SVC) rim.
  • Inferior vena cava (IVC) rim.
  • Posterior rim.
  • Aortic rim.
  • Right upper pulmonary vein rim.
  • AV valve rim (tricuspid valve rim).
• Adequacy: Rims considered adequate if > $5$ mm.
• Total Diameter: Largest diameter of ASD should be characterized. If > $38$ mm, percutaneous closure may not be feasible.
• TEE Views for Rim Measurement:
  • $0$-degree view with aortic valve: Posterior and aortic rim.
  • $120$-degree view (bicaval view): IVC and SVC rim.
  • Rotation from bicaval view: Right upper pulmonary vein rim.
  • Four-chamber view: Posterior and AV valve rim.

Defects Outside Oval Fossa

These include:

• Ostium Primum Defects (Partial AVSD):
  • Key Feature: Common AV valve (five-leaflet) instead of distinct mitral and tricuspid valves.
  • Associated with regurgitation of the left AV valve.
• Sinus Venosus Defects:
  • Superior (most common): Connection between RA and LA near SVC insertion.
  • Inferior: More challenging to visualize, near IVC insertion.

Superior Sinus Venosus Defect

• Subcostal view (short axis, angled upwards).
  • Visualization of defect in tissue at the superior portion between LA and RA.
  • TEE helpful if transthoracic view is suboptimal.
• TEE View (120-degree):
  • SVC entering RA with defect between LA and RA.
  • Location remote to the oval fossa.
  • Requires specific effort to visualize SVC entry.

Inferior Sinus Venosus Defect

• Subcostal view (short axis) for visualizing inferior portion of atria.
• TEE (low gastric load GE junction view at $60$ degrees) to see IVC entering and defect between inferior LA and RA with left-to-right shunting.

Unroofed Coronary Sinus

• Rare.
• Defects in the posterior portion of the left atrial wall connecting to the coronary sinus.
• Echo Findings: True defect or color flow between chambers.

Report Inclusion for Interatrial Communications

• Anatomy: Location and measurements of the defect.
• Right Heart: Size, function, and effect on RVSP.
• Associated Lesions: Partial anomalous pulmonary venous connection (PAPVR) or left AV valve function in partial AVSD.
• Secundum ASD (TEE): Description of rims due to implications for percutaneous closure.

Post-Repair Evaluation

• RV Size and Function: Assess for appropriate remodeling.
• Patch Leaks: Evaluate for necessity of antibiotic prophylaxis.
• Pulmonary Hypertension: Assess RVSP.

Ventricular Communications

Classified from the RV side:

• Perimembranous: Most common, fibrous floor.
• Juxta-arterial: Fibrous roof, under semilunar valves, also called outlet VSD.
• Muscular: Muscle surrounding the entire defect.

Anatomy and Visualization

• Perimembranous VSDs:
  • Parasternal long axis view.
  • Short axis view: $9$ to $12$ o'clock position relative to the aortic valve.
• Juxta-arterial VSDs:
  • Short axis view: $12$ to $3$ o'clock position.

Perimembranous VSDs

• Location: Near semilunar valves.
• Complications: Prolapse of the right coronary cusp causing aortic insufficiency.

Juxta-arterial or Outlet VSDs

• Location: Directly under semilunar valves.

Muscular VSDs

• Complexity: Can be single or multiple channels.
• Description: Number of channels and location.

Restrictive vs. Non-Restrictive VSDs

• Definition: Assessed by continuous wave Doppler through the defect.
• Restrictive: High-pressure gradient between ventricles (>
• Non-Restrictive: Low-pressure gradient.
• VSD jet may contaminate tricuspid regurgitation jet, making RVSP evaluation challenging.

RVSP Estimation in VSD

• RVSP = Systolic Blood Pressure - Pressure Gradient over VSD

Report Inclusion for Ventricular Septal Defect

• Location of defect.
• Measurement of defect.
• Direction of shunt (left-to-right, right-to-left, or bi-directional).
• Systolic pressure gradient over the defect.
• Left ventricular size and function.
• Left atrial size.
• RVSP assessment.

Associated Lesions

• Aortic regurgitation.
• Ventricular outflow tract obstruction.

Post-Repair Evaluation

• Left ventricular size and function.

Patent Ductus Arteriosus (PDA)

• Continuous flow from the aorta to the pulmonary artery.
• Short axis view: Color flow from distal pulmonary artery to RVOT.
• Suprasternal notch view: Connection between descending aorta and pulmonary artery.

Doppler Evaluation

• Continuous flow gradients across the PDA.

Report Inclusion for PDA

• Anatomy: Arch sidedness, location, size, and shunt direction.
• Left ventricular size and function.
• RVSP.
• Associated Lesions: Bicuspid valve, outflow tract obstruction.

Post-Repair Evaluation

• Left ventricular size and function (remodeling).
• Residual leaks.
• Aortic arch obstruction or pulmonary artery branch stenosis.

Summary

• Anatomic evaluation and characterization are vital.
• Classify presence, location, and size using a combination of 2D, color Doppler, and sometimes 3D imaging.
• Pre-tricuspid shunt: Volume loads the right heart.
• Post-tricuspid shunt: Volume loads the left heart.
• Evaluate Pulmonary hypertension.
• Evaluate any Associated lesions.