Nagaraj,   Thanks for your question.    In your question, you noted that you had a heart attack, and that angiography has documented blockages in three vessels, indicating the need for bypass surgery.  It would be unwise to wait for problems to develop before undergoing surgery.  The possible problems include: another heart attack which could be more serious than your last; cardiac arrhythmias (abnormal heart beat); congestive heart failure in which your lungs fill up with fluid, making breathing difficult; and, further progression of the blockages you already have.    All of the above problems would have to be dealt with before any surgery.  They could also complicate and raise the risk of your surgery.  Be thankful that you are feeling well at this time, and keep in mind you have a problem that needs to be taken care to ensure that you have a long healthy life in your future.  Also remember that after your surgery, major changes in your diet and lifestyle will need to be made to stay healthy and prevent this from happening again.  In all likelihood, medication will be required also.   Best wishes.   Martin Cane, M.D.