This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Pharmacology
In a patient of congenital prolonged QT syndrome and intermittent torsedes points, which of the following drug should be prescribed 
Select and explain. 
A. Magnesium sulfate, B. Metaprolol, C. Cardiac pacing, D. Isoprenaline
A: Magnesium sulfate
Answer: A: Magnesium sulfate 
Explanation: Magnesium is a agent of choice for the immediate treatment of torsedes points associated with both congenital and acquired long QT syndrome . Use of intravenous isoproterenol is limited only to acquired long qt syndrome Long term treatment with oral beta blockers is required only for congenital disease Refer Goodman and Gilman 11e 929,930