question: Reapected sir i have a query . I have a brother ,he used to say severe chest pain for 3 days ago ,then on fourth day it continued and found unconscious in the room . He never smoked ,drink alcohol and take any kind of tobacco and drugs . He is a driver by profession in korea . we are worry to listen that he is in hospital on O2 inhalation in unconscious state . What may the causes for this condition? He doesnot have any significant  previous history before.