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': 'The commonest type of congenital heart disease is – \nSelect and explain. \nA. ASD, B. VSD, C. TOF, D. PDA', 'role': 'user'}, {'content': 'Answer: B \nExplanation: VSD is the commonest CHD.\nVSD is the commonest acyanotic CHD.\nAcyanotic congenital heart diseases \n\nAcyanotic heart disease may be of two types : -\n\n\nLeft to right shunts. (ASD, VSD, PDA)\nObstructive lesions (PS, AS, Coarctation of aorta).\n\nA) Left to right shunts\nPatients with a left to right shunts have following features: -\n\nFrequent respiratory tract infection → Because pulmonary circulation is overloaded which may result in pulmonary edema, CHF and infection.\nNo cyanosis → Most of the blood is in pulmonary circulation. So there is no impairment in oxygenation of blood.\nPericardial bulge -4 Frequent chest infections with tachypnea causes the soft rib cage being drawn inward at the diaphragmetic attachments of the ribs. This combined with cardioamegaly gives them a precordial buldge.\nHyperkinetic precordium\nDelayed diastolic murmur in tricuspid or mitral area → Due to increased flow through these areas depending on the type of CHDs.\nCardiomegaly with plethoric pulmonary vasculature on chest X-ray → Due to increased flow through pulmonary circulation (plethoric lung) there is increased volume overload to left side of heart → Cardiomegaly.\n\nB) Obstructive Lesions\n\nObstructive congenital diseases have following features.\n\n\nAbsence offrequent chest infection → Pulmonary circulation is not overloaded.\nThe absence of cyanosis → No defect in pulmonary oxygenation and there is no shunt where arterial and venous blood can mix.\nThe absence of precordial buldge → There is no chest infection or Cardiomegaly.\nHeaving (forcible) cardiac impulse → Obstructive lesions cause concentric hypertrophy of ventricles that produce forcible contraction.\nSystolic thrill due to systolic ejection murmur → When hypertrophied ventricles forcibly pump the blood through stenotic pulmonary or aortic valve, systolic thrill and systolic ejection murmur are produced.\nAbsence of delayed diastolic murmur in mitral or tricuspid area → Blood flow through these area is not increased.\nPresence of delayed corresponding second sound (A2\xa0in AS and P2 in PS) → Because prolonged flow through these area results in delayed closure of that valve.\nNormal sized heart and pulmonary vasculature in chest x-ray → There is concentric hypertrophy, i.e., hypertrophy without dilatation. So, heart size is normal on x-ray.', 'role': 'assistant'}]