What is Heart Attack?
Heart attack results from blood vessel disease in the heart. Coronary heart disease (CHD), sometimes referred to as coronary after disease (CAD), are general names for heart attack (and angina).
A heart attack, or myocardial infarction, occurs when the blood supply to part of the heart muscle itself (the myocardium) is severely reduced or stopped. This occurs when one of the coronary arteries (the arteries that supply blood to the heart muscle) is blocked by an obstruction, such as a blood clot that has formed on plaque due to atherosclerosis. Such an event is sometimes called a coronary thrombosis or coronary occlusion.
If the blood supply is cut off drastically or for a long time, muscle cells suffer irreversible injury and die. Disability or death can result, depending on how much heart muscle is damaged. Sometimes a coronary artery temporarily contracts or goes into spasm. When this happens the artery narrows and blood flow to part of the heart muscle decreases or even stops. What causes a spasm is unclear, but it can occur in normal blood vessels as well as vessels partially blocked by atheroscleorosis. If a spasm is severe, a heart attach may result.
What are the Symptoms of a Heart Attack?
Sometimes the first indications of a heart attack come as warning signals. The actual diagnosis of a heart attack must be made by a physician who has studied the results of several tests. Besides reviewing a patient's complete medical history and giving a physical examination, a doctor will use an electrocardiogram (ECG) to discover any abnormalities caused by damage to the heart. Sometimes a blood test is used to detect abnormal levels of certain enzymes in the bloodstream.
How is a Heart Attack Treated?
When a heart attack occurs, it's critical to recognize the signals and respond immediately. Delaying may increase the damage to the heart and reduce the chance of survival. Anyone experiencing the warning signals of a heart attack should be taken immediately to the nearest hospital with 24-hour emergency cardiac care. People who become unconscious before reaching the emergency room may receive emergency cardiopulmonary resuscitation (CPR).
Most communities have an emergency cardiac care system that can quickly respond. This prompt care for heart attack victims dramatically reduces damage to the heart. In fact, 80 percent of heart attack survivors can return to work within three months. Prompt care for heart attack victims isn't the only reason so many people recover so quickly, but it's an important one.
The importance of time cannot be overemphasized. When a coronary artery gets blocked, the heart muscle doesn't die instantaneously - damage increases the longer an artery remains blocked. If a victim gets to an emergency room fast enough a form of reperfusion therapy (called thrombolysis) sometimes can be performed. It involves injecting injecting a thrombolytic (clot-dissolving) agent, such as streptokinase, urokinase or TPA (tissue plasminogen activator), to dissolve a clot in a coronary artery and restore some blood flow. There drugs must be used within a few (usually 1 -3) hours of a heart attack for best effect. The sooner a drug is used, the more effective it's likely to be.
In the weeks following a heart attack, either PTCA (balloon angioplasty) or coronary artery bypass surgery may be performed to improve the blood supply to the heart muscle. Once part of the heart muscle dies, its function can't be restored. Function may be restored to areas with decreased blood flow, however.
Is There Any Way to Reduce the Chance of a Heart Attack?
Many scientific studies show that certain characteristics increase the risk of coronary heart disease. The four major modifiable risk factors are cigarette / tobacco smoke, high blood cholesterol, high blood pressure and physical inactivity. Other contributing risk factors are diabetes mellitus and obesity.
The Heart Foundation strongly urges people to control their modifiable risk factors. Also, people with angina should take episodes of chest pain seriously and see their doctor before their atherosclerosis leads to a heart attack.