This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S, Subject name: Pharmacology
[{'content': 'Digoxin is contraindicated in: \nSelect and explain. \nA. Supraventricular tachycardia, B. Atrial fibrillation, C. Congestive heart failure, D. Hypertrophic obstructive cardiomyopathy', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. (D) Hypertrophic obstructive cardiomyopathy(Ref: KDT 8th/e p560, 561)Non selective b-blockers (propranolol) are the agents of choice for HOCM.In hypertrophic obstructive cardiomyopathy (HOCM), the LV outflow tract is narrowed during systole due to hypertrophic septum. Obstruction is worsened by:(a) Factors increasing myocardial contractility.-Digitalis-Sympathetic stimulation(b) Factors decreasing LV filling:-Valsalva maneuver-Peripheral vasodilators', 'role': 'assistant'}]