II. Epidemiology
- Incidence: 10-15% of Congenital Heart Disease
- Most common cause of CHD outside infancy
III. Pathophysiology
- See Tet Spell
-
Cyanotic Congenital Heart Disease
- Secondary to Right-To-Left Shunt (related to VSD and often pumonary stenosis)
- May present in first days to month of life with Cyanosis and severe pulmonic stenosis
- Stabilized with PGE-1 infusion followed by endovascular ductus stent
- Similar initial management as with other cyanotic ductus dependent lesions
- Four components
- Primary features responsible for symptoms
- Large Ventricular Septal Defect (VSD)
- Right outflow tract obstruction
- Other features
- Right Ventricular Hypertrophy
- Aorta overides both ventricles (mixing oxygenated and deoxygenated blood)
- Primary features responsible for symptoms
IV. Associated Conditions
- Right aortic arch (25%)
- Atrial Septal Defect (15%)
- Absent pulmonary valve
- Pulmonary atresia
- Pulmonary stenosis
- Atrioventricular septal defect
- Left superior vena cava to coronary sinus
V. Signs
- Oxygen Saturation is always low (e.g. 80%)
- Systolic ejection murmur at left sternal border
- Grade III+ intensity, harsh Systolic Murmur
- Murmur diminishes in intensity during "Tet Spell"
- Single S2 Heart Sound
VI. Diagnostics: Electrocardiogram
VII. Labs
-
Arterial Blood Gas
- Normal arterial pH
- Normal arterial pCO2
- Low arterial pO2
VIII. Imaging
-
Chest XRay
- Heart size normal or small
- Narrow mediastinum
- Heart may appear "boot shaped" in classic presentation
-
Echocardiogram
- Large Ventricular Septal Defect (VSD)
- Right outflow tract obstruction
- Right Ventricular Hypertrophy
- Overriding aorta
IX. Management: Surgery
- Stabilized with PGE-1 infusion followed by endovascular ductus stent in first days of life before ductus closure
- Similar initial management as with other cyanotic ductus dependent lesions
- Subclavian to pulmonary artery shunt (Blalock-Taussig)
- Palliative or temporizing method
- Definitive, total repair
- Repair as newborn or at age 3 years
- Ventricular Septal Defect patch
- Right ventricular outflow tract widening
X. Causes: Cyanotic Episodes
- Tet Spells
-
Hypoxia responsive to Supplemental Oxygen
- Impaired alveolar gas exchange (e.g. Pneumonia, Pulmonary Edema)
-
Hypoxia UNresponsive to Supplemental Oxygen
- Decreased pulmonary Blood Flow via ductus arteriosus (ductus stent Occlusion, closure of unstented ductus)
XI. Complications: Without repair (inoperable cases)
- Affects related to:
- Hypoxia
- Polycythemia
- Symptoms
XII. Complications: Post-surgical correction
- Arrhythmia
- Right ventricular insufficiency
- Right Ventricular Failure
- Pulmonary insufficiency
- Left ventricular insufficiency
XIII. Prognosis
- Survival post-surgical repair: >95%
- Cognitive development may be impaired
XIV. References
- Broder (2023) Crit Dec Emerg Med 37(9): 22-3
- Civitarese and Crane (2016) Crit Dec Emerg Med 30(1): 14-23
- Cyran (1998) PREP review lecture, October, Phoenix
- Merenstein (1994) Pediatrics, Lange
- Tsze and Spangler in Herbert (2015) EM:Rap 15(4): 2-3
- Saenz (1999) Am Fam Physician 59(7):1857-66 [PubMed]