Q. Eisenmenger’s physiology will result from an unoperated: a. Small atrial septal defect b. Tetralogy of Fallot c. Large patent ductus arteriosus d. Coarctation of the aorta e. Pulmonary stenosis Answer: Option c Explanation: Large left to right shunts (e.g. Large PDA, VSD, ASD) lead to excessive pulmonary blood flow and irreversible changes in pulmonary capillaries which cause pulmonary arterial hypertension and ultimately reversal of cardiac shunt. Small left to right shunts usually don’t cause Eisenmenger’s syndrome. TOF and PS have decreased pulmonary blood flow and COA is a left sided obstructive lesion which do not cause Eisenmenger’s syndrome.
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