What would left anterior descending coronary artery blockage cause?

Heart attack: It depends on how bad the blockage is. If severe it could cause actual damage, a heart attack. If less severe it could cause chest pain on exertion. If it is minor, there could be no symptoms at all. The symptoms can be chest pain, shortness of breath, or fatigue. As that artery supplies a large area of the heart muscle, it has been referred to as the widow-maker.

Left anterior descen: This has been called the "widow maker" artery that can cause angus, heart attack or myocardial infarction, or sudden death.