This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Anatomy
[{'content': 'Propranolol is useful in the treatment of all of the following except \nSelect and explain. \nA. Angina, B. Paial atrioventricular block, C. Idiopathic hyperophic subaic cardiomyopathy, D. Familial tremor', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ref-KDT 6/e p142,143 Beta blockers are contraindicated in hea block because this can conve paial AV block to complete AV block. These agents are the drugs if choice for HOCM', 'role': 'assistant'}]