What would happen if the coronary artery got blocked?

The coronary arteries is, of which there are actually two one right and one left, are the first ones in the coronary supply, i.e. they are the root suplly coming directly from the aorta. Other than the fact that suply so the heart is only during ventricular diastole (I have attempted to explain the point in other questions) the odd thing about the heart is that its arters are terminal. Of course by this i do not mean they just stop they to still turn into cappilary bweds then veins. What I mean is they to not join up to each other as they do in many other organs. The reason they usually do this is so that if there is a blockage somewehre supply to that region is not cut off. Think about it like a stram with holes in it, if you blow water through the straw is will burst out through all the holes. If there was a blockage somewhere in the straw then water will not come from the holes below the blockage. If you make the straw into a loop and blow water through it, even with a blockage the all of the holes will have water coming out of them still. Well if one of the coronary arteries, as there is no loop, the supply to all the heart that comes after the blockage will stop. This mean the heart will no longer receive any oxygen or nutriengs and will lead to a heart attack.

That usually leads to a heart attack, also known as a myocardial infarction.