Tetralogy of Fallot vs Eisenmenger syndrome
How to tell Tetralogy of Fallot and Eisenmenger syndrome apart when a board question makes them look alike.
TOF is primary cyanotic anatomy; Eisenmenger is late shunt reversal after an initially left-to-right lesion.
Side by side
Primary cyanotic defect with VSD, overriding aorta, RV outflow obstruction, RVH, tet spells, and squatting relief.
Late pulmonary hypertension from chronic left-to-right shunt causing reversal to right-to-left shunt, cyanosis, and clubbing.
Anterior malalignment of the outflow septum creates RV outflow obstruction and right-to-left shunting.
Long-standing pulmonary overcirculation damages pulmonary vessels until right-sided pressures exceed left-sided pressures.
Boot-shaped heart, harsh systolic murmur from RV outflow obstruction, and cyanotic spells point TOF.
History of unrepaired VSD/ASD/PDA with new cyanosis, clubbing, and pulmonary hypertension points Eisenmenger.
The trap
Cyanosis alone cannot distinguish congenital right-to-left anatomy from acquired shunt reversal.
Watch it explained
The repair move
For cyanotic congenital disease, ask whether cyanosis was early anatomy or late reversal.
Try a free question
CoreA cyanotic child squats during spells. Imaging and exam support VSD, overriding aorta, right ventricular outflow obstruction, and right ventricular hypertrophy. Which diagnosis is most likely?
Show answer and explanation
Answer: A. Tetralogy of Fallot. Tetralogy of Fallot is a primary cyanotic conotruncal defect with RV outflow obstruction and right-to-left shunting across VSD.
Why the other choices are tempting
- B. Eisenmenger syndrome is late shunt reversal after chronic pulmonary hypertension from an unrepaired left-to-right shunt.
- C. TGA has parallel circulations and severe neonatal cyanosis dependent on mixing.
- D. Truncus arteriosus has a single arterial trunk.
- E. ASD is usually acyanotic with fixed split S2 unless severe late pulmonary hypertension develops.
Flashcards
Tap a card to flip it.
What is the fastest separator for Tetralogy of Fallot vs Eisenmenger syndrome?
TOF is primary cyanotic anatomy; Eisenmenger is late shunt reversal after an initially left-to-right lesion.
What clue should make you choose Tetralogy of Fallot?
Primary cyanotic defect with VSD, overriding aorta, RV outflow obstruction, RVH, tet spells, and squatting relief.
Quick answers
What is the fastest way to tell Tetralogy of Fallot from Eisenmenger syndrome?
TOF is primary cyanotic anatomy; Eisenmenger is late shunt reversal after an initially left-to-right lesion.
What is the key clue for Tetralogy of Fallot?
Primary cyanotic defect with VSD, overriding aorta, RV outflow obstruction, RVH, tet spells, and squatting relief.
What is the key clue for Eisenmenger syndrome?
Late pulmonary hypertension from chronic left-to-right shunt causing reversal to right-to-left shunt, cyanosis, and clubbing.
What is the common trap with Tetralogy of Fallot vs Eisenmenger syndrome?
Cyanosis alone cannot distinguish congenital right-to-left anatomy from acquired shunt reversal.