Registered Nurse here; First blood pressure usually drops with Myocardial Infraction (Heart Attack), for the heart muscle is dying and not pumping as effectively as it should. For the blockage, this is a question for one person, and that would be your cardiologist. Some blockage can be removed without surgery, via dilation and with some medications. Many variables come into play. I have been a Critical Care Nurse and E.R nurse for 24 years. Only a cardiologist can give you complete accurate information concerning a blockage. Thanks for allowing me to address a well worded, very important question.