A heart attack (myocardial infarction) is the death of heart muscle from the sudden blockage of a coronary artery by a blood clot.
Coronary arteries are blood vessels that supply the heart muscle with blood and oxygen. Blockage of a coronary artery deprives the heart muscle of blood and oxygen, causing injury to the heart muscle. Injury to the heart muscle causes chest pain / pressure. If blood flow is not restored to the heart muscle within 20 to 40 minutes, irreversible death of the heart muscle will begin to occur. The dead heart muscle is eventually replaced by scar tissue.
Atherosclerosis is a gradual process by which collection of cholesterol is deposited in the walls of arteries. This causes hardening of the arterial walls and narrowing of the inner channel (lumen) of the artery. Arteries that are narrowed by atherosclerosis cannot deliver enough blood to maintain normal function of the parts of the body they supply. Smoking cigarettes, high blood pressure, elevated cholesterol, and diabetes mellitus can accelerate atherosclerosis and lead to the earlier onset of symptoms and complications, particularly in those people who have a family history of early atherosclerosis.
Angina pectoris is chest pain / pressure that occurs when the blood and oxygen supply to the heart muscle cannot keep up with the needs of the muscle. An insufficient supply of oxygen to the heart muscle causes angina. Angina that occurs with exercise or exertion is called exertional angina. Exertional angina usually feels like a pressure, heaviness, squeezing, or aching across the chest. This pain may travel to the neck, jaw, arms, back, or even the teeth, and may be accompanied by shortness of breath, nausea, or a cold sweat. Exertional angina typically lasts from one to 15 minutes and is relieved by rest or by taking nitroglycerin by placing a tablet under the tongue. Exertional angina may be the first warning sign of advanced coronary artery disease. Chest pains that just last a few seconds rarely are due to coronary artery disease. Angina at rest more commonly indicates that a coronary artery has narrowed to such a critical degree that the heart is not receiving enough oxygen even at rest. Unlike a heart attack, there is no permanent muscle damage with either exertional or rest angina.
What are the symptoms of a heart attack?
Pain, fullness, and/or squeezing sensation of the chest
Jaw pain, toothache, headache
Shortness of breath
Nausea, vomiting, and/or general upper middle abdomen discomfort
Heartburn and/or indigestion
Arm pain (more commonly the left arm, but may be either arm)
Upper back pain
General malaise (vague feeling of illness)
No symptoms (Silent heart attacks are especially common among patients with diabetes mellitus.)
What are the risk factors for atherosclerosis and heart attack?
High Blood Cholesterol: A high level of cholesterol in the blood is associated with an increased risk of heart attack because cholesterol is the major component of the plaques deposited in arterial walls.
High Blood Pressure: Both high systolic pressure (when the heart beats) and high diastolic pressure (when the heart is at rest) increase the risk of heart attack.
Tobacco Use (Smoking): Tobacco and tobacco smoke contain chemicals that cause damage to blood vessel walls, accelerate the development of atherosclerosis, and increase the risk of heart attack.
Diabetes Mellitus: Both insulin dependent and non-insulin dependent diabetes mellitus are associated with accelerated atherosclerosis throughout the body. Therefore, patients with diabetes mellitus are at risk for reduced blood flow to the legs, coronary heart disease, erectile dysfunction, and strokes at an earlier age than non-diabetic subjects.
Male Gender: At all ages, men are more likely than women to develop atherosclerosis and coronary heart disease. Some scientists believe that this difference is partly due to the higher blood levels of HDL cholesterol in women than in men. However, this gender difference narrows as men and women grow older.
Family History of Heart Disease: Individuals with a family history of coronary heart diseases have an increased risk of heart attack.
Sedentary lifestyle: Exercise decreases the risk of developing heart attacks