Coronary occlusion
A coronary occlusion is the partial or complete obstruction of blood flow in a coronary artery. This condition may cause a heart attack. In some patients coronary occlusion causes only mild pain, tightness or vague discomfort which may be ignored; however, the myocardium, the muscle tissue of the heart, may be damaged. According to Robert K. Massie's "Nicholas and Alexandra: The Fall of the Romanov Dynasty", Tsar Nicholas II may have suffered a coronary occlusion right before he was toppled from his throne during the Russian Revolution in 1917.