In some circumstances, the plaque can rupture or break open, leading to the formation of a blood clot in the coronary artery. This clot can completely occlude or block the artery. This prevents oxygen-rich blood from being delivered to the heart muscle beyond that blockage and that part of the heart begins to die. This is a myocardial infarction or heart attack. If the situation is not recognized and treated quickly, the affected part of the muscle cannot be revived. It dies and is replaced by scar tissue. Long term, this scar tissue decreases the heart's ability to pump effectively and efficiently and may lead to ischemic cardiomyopathy (ischemic=decreased blood supply + cardio=heart + myo=muscle + pathy=disease).
Heart muscle that lacks adequate blood supply also becomes irritable and may not conduct electrical impulses normally. This can lead to abnormal electrical heart rhythms including ventricular tachycardia and ventricular fibrillation. These are the heart arrhythmias associated with sudden cardiac death. Continue Reading