There are several factors known to cause this dangerous disease. Ischemic heart disease may evolve as the plaque develops in the arteries. A decreased blood flow happens when one or more of these arteries turns somehow blocked, fully or not. The 4 main coronary arteries are present in the heart’s coverage as well as four basic arteries. Those are circumflex, left, right, and left anterior descending arteries. Those arteries are extra important as they provide necessary nutrition to the main human organ – heart.