This means there is one or more totally blocked coronary arteries and one has had damage done to the heart
muscle because of a heart
attack. There is an area (or areas) of the heart
muscle that has become scar tissue (scarring, scarred) because of the MI. This area would not be able to make functional use of any oxygen even if blood flow to that area of the heart were completely restored.
Anterior is front and lateral is side, this is the area of cardiac muscle that shows the perfusion defect.