TOF is a cyanotic congenital heart disease consisting of four defects that cause right-to-left shunting and cyanosis.
Most Common Cause of Cyanotic CHD After 1 Year of Life
Mnemonic: "PROVe" (4 Defects of TOF)
- Pulmonary
Stenosis (Narrow Pulmonary Valve)
- Right
Ventricular Hypertrophy (Thickened RV Wall)
- Overriding
Aorta (Aorta Covers VSD)
- Ventricular
Septal Defect (Hole Between Ventricles)
CAUSES OF TOF
- Abnormal Development of the Bulbar Septum (Failure of Proper Aortic-Pulmonary Separation)
Mnemonic: "TOF = Trouble in Septal Fusion"
SYMPTOMS OF TOF
• Mild TOF (Less Cyanosis at Birth)
• Severe TOF (Cyanosis from Early Infancy)
- Cyanosis (Blue Baby) → Worsens with
Crying, Feeding
- "Tet Spells" (Sudden
Cyanosis, Child Becomes Breathless & Unconscious)
- Squatting Relieves Symptoms
(Increases Blood Flow to Lungs)
- Clubbing of Fingers & Toes
- Growth Retardation
Mnemonic: "5 C’s of TOF"
- Cyanosis
- Crying
Triggers Tet Spells
- Clubbing
- Child Squats
to Improve Circulation
- Cardiac
Murmur (Loud Systolic Murmur)
HEART MURMUR IN
TOF
- Loud Ejection Systolic Murmur (Pulmonary Area) → Due to Pulmonary Stenosis
- Single S2 Sound (No Pulmonary Component)
Mnemonic: "TOF = Turbulent Outflow Flow"
COMPLICATIONS OF
TOF
• Severe Hypoxia & Brain Damage (If Tet Spells Are Frequent)
• Polycythemia (High RBCs to Compensate for Low Oxygen)
• Brain Abscess & Stroke (Due to Low Oxygen)
• Endocarditis (Heart Infection)
Mnemonic: "TOF = P-B-E-E" (Polycythemia, Brain Abscess, Endocarditis, Eisenmenger’s Syndrome)
DIAGNOSIS OF TOF
- ECG → Right Ventricular Hypertrophy (RVH)
- Chest X-ray → "Boot-Shaped Heart" (Due to RVH)
- Echocardiography (ECHO – Best Test!) → Confirms 4 Defects
- Oxygen Saturation Test → Low Oxygen Levels in Blood
Mnemonic: "ECHO-BOOT" (Tests for TOF)
TREATMENT OF TOF
1. MEDICAL MANAGEMENT
(Before Surgery)
- Prostaglandin (PGE1) in Neonates → Keeps Ductus Open (Improves Lung Blood Flow)
- Beta-Blockers (Propranolol) → Reduce Tet Spells
- Oxygen Therapy & IV Fluids
2. SURGICAL
MANAGEMENT
- Complete Repair (Best Treatment, Done Before 5 Years of Age)
- Palliative Blalock-Taussig Shunt (If Baby Too Small for Surgery)
Mnemonic: "B-P-S" (Beta-Blockers, Palliative Shunt, Surgery)
PROGNOSIS OF TOF
- Good if Treated Early
- Untreated → Death Due to Severe Cyanosis & Heart Failure
Mnemonic: "TOF = Treat Or Fatal"
FINAL REVISION WITH MNEMONICS
- TOF Defects = "PROVe" (Pulmonary Stenosis, RVH, Overriding Aorta, VSD)
- Symptoms = "5 C’s" (Cyanosis, Crying Triggers Tet Spells, Clubbing, Child Squats, Cardiac Murmur)
- Complications = "P-B-E-E" (Polycythemia, Brain Abscess, Endocarditis, Eisenmenger’s Syndrome)
- Diagnosis = "ECHO-BOOT" (ECHO, Boot-Shaped Heart on X-ray)
- Treatment = "B-P-S" (Beta-Blockers, Palliative Shunt, Surgery)
- Prognosis = "TOF = Treat Or Fatal"
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