Understanding Congenital Heart Disease

Dec 2, 2024

Congenital Heart Disease Lecture Notes

Overview

  • Congenital heart disease: group of conditions present at birth with structural heart abnormalities.
  • Most common birth defects.
  • Three main types:
    • Left to Right Shunting (Acyanotic): Blood moves from left to right side of heart, does not usually cause cyanosis.
    • Right to Left Shunting (Cyanotic): Deoxygenated blood moves to the left side, causes cyanosis.
    • Obstructive Defects: Restrictions in blood flow pathways.

Heart Circulation Basics

  • Normal blood flow: Right atrium → Right ventricle → Pulmonary artery → Lungs → Pulmonary veins → Left atrium → Left ventricle → Aorta.
  • Pressure dynamics: Higher on left vs. right side.

Left to Right Shunting

Ventricular Septal Defect (VSD)

  • Most common congenital heart defect (20%).
  • Different types based on location: Outlet, Inlet, Perimembranous, Muscular.
  • Small VSDs often asymptomatic; larger can cause pulmonary hypertension, Eisenmenger syndrome.
  • Diagnosed with echocardiography.
  • Treatment can range from observation to surgical closure.

Atrial Septal Defect (ASD)

  • 10% of congenital heart defects, more common in females.
  • Types: Sinus venosus, Ostium primum, Ostium secundum, Unroofed coronary sinus.
  • Small ASDs asymptomatic until adulthood.
  • Can cause atrial arrhythmias, heart failure.

Patent Ductus Arteriosus (PDA)

  • Connection between aorta and pulmonary artery remains open post-birth.
  • More common in premature infants.
  • Causes pulmonary hypertension, right heart strain.
  • Treatment: NSAIDs or surgery.

Right to Left Shunting (Cyanotic)

Tetralogy of Fallot

  • Includes four defects: VSD, Pulmonary stenosis, Right ventricular hypertrophy, Overriding aorta.
  • Symptoms: Cyanosis, poor growth, "Tet spells" (agitation and cyanosis).
  • Definitive treatment is surgical.

Transposition of the Great Arteries

  • Aorta and pulmonary artery are swapped.
  • Requires immediate intervention; prostaglandins and surgery.

Epstein's Anomaly

  • Malformed tricuspid valve, can lead to right to left shunting.
  • Symptoms vary widely.
  • Associated with lithium use during pregnancy.
  • Treatment often requires surgery.

Obstructive Defects

Aortic Coarctation

  • Narrowing of the aorta, usually near the ductus arteriosus.
  • Often associated with bicuspid aortic valve and Turner syndrome.
  • Treatment options include surgery or balloon dilation.

Additional Notes

  • Certain defects can allow emboli to cross from venous to arterial system (risk of stroke).
  • Diagnostics: Echocardiography is the gold standard, supplemented by CT/MRI as needed.
  • Management includes medical therapy, catheter interventions, and surgical repair.