This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pediatrics
[{'content': "Which one of the following congenital heart diseases has cyanosis without cardiomegaly and/or congestive heart failure – \nSelect and explain. \nA. Transposition of great arteries, B. Fallot's tetralogy, C. Congenital mitral regurgitaion, D. Congenital pulmonary stenosis", 'role': 'user'}, {'content': "Answer: B \nExplanation: Cardiomegaly and CHF do not occur in Fallot's tetrology.\nNo Cardiomegaly\n\n\nFirst you should know the following facts : -\n\n\nPressure overload to ventricles causes concentric hypertrophy without dilatation.\nVolume overload to ventricles causes hypertrophy with dilatation → Eccentric hypertrophy.\n\n\nDue to pulmonary stenosis, there is pressure overload to right ventricle → Concentric hypertrophy of right ventricle without dilatation → No Cardiomegaly.\n\nNo CHF\n\nThe VSD of TOF is always large enough to allow free exit to the right to left shunt.\nSince the right ventricle is effectively decompressed by the VSD, CHF never occurs in TOF.", 'role': 'assistant'}]