CORONARY HEART DISEASE

also called Ischemic Heart Disease, the effect of an inadequate supply of oxygen-rich blood to the heart muscle (myocardium) because of narrowing or blocking of a coronary artery by fatty and fibrous tissue (see arteriosclerosis). If the oxygen depletion is extreme, the effect may be the death of a section of heart muscle (see myocardial infarction); if the deprivation is insufficient to cause infarction, the effect may be angina pectoris (q.v.). Progressive destruction of the myocardium occurs with repeated attacks. Both conditions can be fatal because they can cause left ventricular failure or ventricular fibrillationan uncontrolled and uncoordinated twitching of the ventricle muscle (the ventricles are the lower chambers of the heart) that induces sudden cardiac death. Coronary bypass surgery or balloon angioplasty are indicated if medication and diet do not control progressive coronary heart disease and if the myocardial damage is not too extensive.