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Common Congenital Heart Lesions - page 9 / 126





9 / 126

9 of 126

Cyanotic 1. Tetralogy of Fallot

Clinical Presentation: patients with TOF present in childhood with dyspnea on exertion or after feeding or crying (vasodilation of systemic vasculature increases right to left shunt). Other symptoms: irritability, cyanosis, hyperventilation, syncope, convulsions. Major symptom: child reflexively squats down during spells (“kinking” of femoral arteries increases systemic resistance and decreases right to left shunt and directs more blood from RV to lungs)

Physical Findings: Moderate pulmonary stenosis: mild cyanosis, especially on lips, mucus membranes, and digits. Severe pulmonary stenosis causes:

  • 1.

    Profound cyanosis within a few days of birth

  • 2.

    Clubbing of fingers and toes due to chronic hypoxemia

  • 3.

    Palpable heave along left sternal border indicates RVH

  • 4.

    Single S2 (pulmonary component is inaudible)

  • 5.

    Systolic ejection murmur heard best at left upper sternal border (from PS)

Diagnostic Imaging and Testing: A. Chest x-ray: “Boot-shaped heart,” prominence of RV, decrease in size of main pulmonary artery, decreased pulmonary vascular markings

  • B.

    ECG: RVH and Right axis deviation

  • C.

    Echo and Cardiac Cath: shows R ventricle tract anomaly, malaligned VSD, RVH

Treatment: Complete surgical correction at age 1: closure of VSD and enlargement of subpulmonary infundibulum. If need to delay complete correction until later in childhood, then palliative surgery in infancy: create connection between aorta and PA, results in L to R shunt and increases blood flow to lungs. Antibiotic prophylaxis.

Etiology: Abnormal anterior and superior displacement of the ventricular outflow tract (infundibular portion of the IV septum) resulting in four anomalies:

  • 1.

    Ventricular Septal Defect due to septal malalignment

  • 2.

    subvalvular pulmonic stenosis (misaligned infundibular septum obstructs

outflow tract)

  • 3.

    Overriding aorta that receives blood from both ventricles

  • 4.

    RVH (due to increased pressure caused by pulmonary stenosis)

Pathology: see Etiology Pathophysiology: Subvalvular pulmonary stenosis causes resistance to flow through right outflow tract. Most of the deoxygenated blood in the RV is diverted through VSD and into aorta, magnitude of shunt depends on severity of PS

Epidemiology: most common cyanotic congential heart lesion seen AFTER infancy, associated with other defects, such as right-sided aortic arch and ASD

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