Heart Attack (myocardial infarction) |
OverviewA heart attack or myocardial infarction is an injury to the heart muscle. It occurs when the blood supply to part of the heart muscle is severely reduced or stopped usually by a blood clot that blocks a coronary artery. According to the Heart and Stroke Foundation of Canada there are over 70000 heart attacks in this country each year. In 2001 (the latest year for which statistics are available) 19000 Canadians died from heart attacks. The good news is that today over 80% of heart attack patients admitted to hospital survive. CausesOver 90% of heart attacks occur as a result of atherosclerosis the medical term given to the process in which deposits of fatty substances cholesterol calcium and so on build up in the inner lining of an artery. This buildup is called plaque. Plaque contributes to a narrowing of the arteries. If the plaque breaks loose it can form a clot that blocks the flow of blood to the heart muscle. If the blood supply to the heart is cut off for longer than several minutes muscle cells in the affected area suffer irreversible injury and die. As heart cells cannot reproduce muscle damage from a heart attack is permanent. A heart attack can result in disability or even death depending on how much and where the heart muscle is damaged. Heart attacks can also be triggered by a severe contraction or spasm in one of the coronary arteries. 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-appearing blood vessels as well as vessels partly blocked by atherosclerosis. Certain factors contribute to atherosclerosis and increase your risk of a heart attack. While some cannot be controlled many can through simple lifestyle improvements. According to the Heart and Stroke Foundation of Canada having even one of these risk factors will increase your chances of developing heart problems:
You can modify or eliminate many of these risk factors to reduce your chances of having a first or second heart attack. SymptomsSome heart attacks are sudden and intense -- the "movie heart attack" where no one doubts what's happening. The victim suffers a crushing squeezing pain in the chest. This is often accompanied by pains in the left arm and jaw breathlessness nausea sweating and anxiety. But heart attack symptoms are different for different people. Most heart attacks start slowly with mild pain or discomfort. Some people particularly women may experiences vague chest discomfort or think they are having severe heart burn. Often people affected aren't sure what's wrong and wait too long before getting help. If you see or have any of the symptoms listed below immediately call 9-1-1. A heart attack is a life-and-death emergency -- every second counts.
Remember not all these signs occur in every heart attack. Sometimes they go away and return. If even some occur do not waste time. Of those who die of heart attacks most die within the first hour after the onset of signs and symptoms. It is important to quickly get to a hospital where doctors can administer new medications and treatments unavailable to patients in years past. For example clot-busting drugs can stop some heart attacks in progress reducing disability and saving lives. But to be effective these drugs must be given soon after symptoms first appear. TreatmentAfter you call 9-1-1 the operator may recommend that you take an aspirin. This will inhibit blood clotting and help maintain blood flow through a narrowed artery. It is best to chew the aspirin rather than swallowing it so that it is absorbed rapidly. If the 9-1-1 operator doesn't talk to you about taking an aspirin health care professionals in the hospital Emergency Department will give you an aspirin if it's right for you. Research shows that chewing an aspirin early in the treatment of a heart attack along with other emergency treatments can significantly improve your chances of survival. A heart attack could trigger a potentially fatal unstable heart rhythm or "ventricular fibrillation". An automatic external defibrillator (AED) that shocks the heart back into a normal rhythm can provide emergency treatment before a person suffering a heart attack reaches the hospital. Most ambulance teams carry portable defibrillators. Many police and fire rescue units also carry defibrillators and may respond before an ambulance. Once you've been diagnosed with a heart attack initial treatment will be aimed at restoring blood flow to the heart muscle in order to minimize the damage and prevent complications. You may have coronary angioplasty to open a blocked artery and/or your doctor may administer a thrombolytic drug to help dissolve the blood clot along with a second drug called a platelet IIb/IIIa receptor blocker or super-aspirin. The second drug which is more potent than regular aspirin helps prevent new clots from forming. If you are suffering from severe chest pain you may also be given a powerful a powerful analgesic such as morphine. Your heart will be carefully monitored for 24 to 48 hours. If your progress is satisfactory you will be encouraged to start spending more and more time out of bed. When you are ready you will begin a series of tests to evaluate the state of your heart muscle and coronary arteries. The results will help your doctor determine the next step in treatment. For example he may want to prescribe an ACE inhibitor and/or diuretic to help the heart pump more efficiently. In more serious cases there may be a need for bypass surgery or a pacemaker. PreventionYour doctor may prescribe a beta blocker cholesterol lowering medication and/or daily low-dose aspirin to help reduce the risk of another heart attack. He may also tell you to quit smoking not to drink too much alcohol follow a healthy low-fat diet and exercise regularly. (Never start an exercise program without first consulting your doctor.) Your doctor may also refer you to a cardiac rehabilitation program where you will receive ongoing support and encouragement as you continue to recover. Most people lead full active lives after a heart attack. But you may have to make some positive changes in your lifestyle be patient and adopt a "can-do" attitude. A healthy lifestyle can help prevent the narrowing of arteries that supply blood to the heart and lead to a first or second heart attack. To reduce your risk the Heart and Stroke Foundation of Canada recommends the following: Keep blood pressure at healthy levels Adults should have their blood pressure checked regularly especially if high blood pressure runs in the family. People with high blood pressure should ask their doctors how to reduce it. Blood pressure can often be brought into normal ranges by lifestyle changes such as: losing excess weight; exercising; reducing salt intake; increasing consumption of potassium-rich foods and managing stress levels. Sometimes medication may also be required. Blood pressure lowering medication must be taken exactly as directed. Keep cholesterol at healthy levels Adults should have their blood cholesterol levels checked regularly especially if there's a family history of high cholesterol. People with high cholesterol levels should ask their doctors how to reduce them. Blood cholesterol levels can sometimes be lowered by reducing the amount of fat in the diet. Sometimes cholesterol lowering medications may also be needed. Stop smoking A smoker's risk of coronary heart disease is far higher than that of a non-smoker. Smokers should ask their doctors for advice on how to quit smoking. There are many smoking cessation programs and cessation aids to help smokers quit. Exercise regularly Regular exercise can reduce your risk of developing coronary heart disease. Exercise increases levels of "good" (High Density Lipoprotein or HDL) cholesterol helps you manage stress and improves the efficiency of the heart lungs and muscles. Even modest levels of low-intensity exercise are beneficial if done regularly. Control diabetes Patients with diabetes should take steps to manage it well. Diabetes (especially poorly controlled diabetes) increases the risk of developing coronary heart disease. Maintain a healthy body weight Adults should keep their body weight as close as possible to the ideal body weight for their age and build. (If you are not sure of your ideal body weights you should consult your doctor.) Exercise and proper diet are two key factors in maintaining a healthy weight. People who are more than 30% over their ideal weight are more likely to develop coronary heart disease and stroke even if they have no other risk factors. Added weight increases the strain on the heart and contributes to high blood pressure and high blood cholesterol. It can also lead to type-2 (adult-onset) diabetes. Learn to control stress Stress is often associated with unhealthy activities such as smoking overeating excessive drinking worrying or outbursts of anger. People under severe stress should consult their doctors for advice on how to manage stress. Stress management programs focus on learning to identify prioritize and discuss problems eating well getting enough sleep and exercising. |