## Diagnosis and Management of Tetralogy of Fallot **Key Point:** While PGE1 is useful for maintaining ductal patency in neonates with severe cyanosis, it is NOT a definitive treatment. Surgical repair is the only definitive therapy for TOF. ### Diagnostic Modalities in TOF | Investigation | Finding | Significance | |---------------|---------|---------------| | Chest X-ray | Boot-shaped heart (coeur en sabot) | RV hypertrophy + decreased pulmonary vasculature | | ECG | Right axis deviation, RVH pattern | Reflects RV hypertrophy | | Echocardiography | All four defects visualized | Gold standard; non-invasive; guides surgery | | Cardiac catheterization | RV-to-PA pressure gradient | Rarely needed now (echo sufficient) | **High-Yield:** The "boot-shaped" heart is pathognomonic for TOF and results from the combination of RV hypertrophy (upturned apex) and decreased pulmonary blood flow (narrow mediastinum). ### Medical vs. Surgical Management **Medical Management (Temporary/Supportive):** - Prostaglandin E1: maintains patent ductus arteriosus (PDA) → increases pulmonary blood flow in neonates - Beta-blockers: reduce RVOT spasm and improve exercise tolerance - Oxygen therapy: increases SVR, reducing right-to-left shunt - Fluid management: avoid dehydration (increases blood viscosity and cyanosis) **Surgical Management (Definitive):** - Primary repair in infancy: RVOT obstruction relief + VSD closure - Timing: typically 3–6 months of age - Success rate: >95% with modern techniques **Clinical Pearl:** PGE1 is a temporizing measure in severely cyanotic neonates awaiting surgery. It does NOT repair the underlying anatomy—it merely maintains ductal patency to allow mixing of systemic and pulmonary circulations. **Mnemonic for TOF Management:** **PGE1 buys TIME** — Prostaglandin E1 keeps the ductus arteriosus open, buying time until definitive surgical repair can be performed.
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