Ischemic heart disease is a cardiovascular disorder caused by reduced blood flow to the heart muscle, most commonly due to narrowing or blockage of the coronary arteries by atherosclerotic plaques. The resulting decrease in oxygen supply can lead to chest pain (angina), shortness of breath, myocardial infarction (heart attack), heart failure, or arrhythmias. Major risk factors include hypertension, diabetes, smoking, high cholesterol, obesity, physical inactivity, and family history. Treatment involves lifestyle modifications, medications to improve blood flow and reduce cardiac workload, and, when necessary, revascularization procedures such as angioplasty or coronary artery bypass surgery.