The heart of the matter
Heart attack also called a myocardial infarction is all too common in the United States. Knowing the early warning signs and getting prompt medical attention can increase your chances of survival.
A heart attack is the death of heart muscle from loss of blood supply. The most common cause is coronary artery disease. The coronary arteries supply oxygen to the heart muscle. Coronary artery disease develops when cholesterol and other fatty deposits called plaque are deposited on the artery walls. The accumulation of plaque over time causes narrowing of the coronary arteries, a process called atherosclerosis. When a blood clot forms on top of the plaque, blood can no longer pass through the artery, and a heart attack results. A heart attack can result in cardiac arrest when the heart stops pumping completely.
Most people who survive for a few days after a heart attack can expect full recovery, but must make a serious commitment to lifestyle changes that address the underlying causes of the attack.
A heart attack is a medical emergency and often occurs without warning. If you think you are suffering from a heart attack, there is no time to consider whether you have all the risk factors. You should, however, generally be aware that the chances of suffering from a heart attack are strongly associated with lifestyle and age. If you are an older man who eats a diet high in fat, does not exercise regularly, smokes, has high blood pressure, and has a family history of premature coronary disease, you are at increased risk of having one.
Heart attacks can occur anytime, but are most common between 4:00 a.m. and 10:00 a.m. due to larger adrenaline amounts being released in the morning hours. Half of all heart attack deaths occur in the first three to four hours after they begin. Time is critical. Prompt treatment increases the chances of survival. Therapies are most effective within six hours after heart attack symptoms begin, and most deaths occur because patients don't make it to the hospital in time. More than 90% of patients who make it to the hospital survive, and 88% of heart attack survivors under age 65 can return to work within three months.
However, the permanent death of some heart muscle from a heart attack is common. The amount and condition of the remaining heart muscle determine how well the patient will recover as well as his or her life expectancy.
Rehabilitation is an important part of recovery. After several days of rest, heart attack patients gradually increase their activity. Lowering risk factors for coronary artery disease and close monitoring for recurrence are critical to successful recovery.
How Common Are Heart Attacks?
The American Heart Association reports that every year more than one million Americans have a heart attack. About 650,000 of these will be first attacks and 450,000 will be recurrent attacks. About one-third of the people experiencing these attacks will die of them. The good news is that 12,000,000 people who have suffered heart attacks and/or angina pectoris are nonetheless alive today.
Treatment for a heart attack occurs at two levels. The first is the immediate, emergency response to stabilize the patient's condition: open blocked arteries and restore blood flow. This includes administering oxygen to aid breathing and medication to clear a blocked coronary artery.
The second is the long-term rehabilitation and treatment of the underlying causes of the attack in order to prevent recurrence. In the short term, medications and sometimes surgery will open the artery blockage causing the heart attack. Prevention strategies to halt the progression of coronary artery disease include diet modification, exercise, and stress reduction.
The death of heart muscle from a heart attack is irreversible. However, the underlying causes of a heart attack can be addressed and controlled to help prevent another attack.
Therapies are categorized by those designed for immediate treatment and those for post-attack treatment.
- Thrombolytic drugs to dissolve the clot: streptokinase (Steptase), alteplase (Activase), anistreplase (Eminase), or reteplase (Retavase)
- Oxygen administration
- CPR and defibrillation to restart stopped heart
- Pain medication such as morphine for alleviation of pain and anxiety
- Surgery if needed
- Daily intake of aspirin
- Various drugs to decrease the heart's demand for oxygen
- Various drugs to discourage blood clot formation
- Surgery if needed
Therapies are prescribed according to your specific needs. It is usually important to address the underlying cause of the heart attack. The best therapy is making a transition to live a healthier life. Drugs are available to aid recovery. Anticoagulant medications are usually prescribed for three to six months after the heart attack to help prevent clotting. Other medications such as beta-blockers may also be prescribed to lower the risk of death and a second heart attack. Surgery is an option for severely damaged heart.
The two most commonly performed procedures to unblock the blood vessels leading to the heart are angioplasty and coronary bypass surgery. Angioplasty is the fastest method of opening a blocked artery. It can be effective in 95% of patients, usually within an hour. But sometimes angioplasty is technically difficult or, when combined with medication, fails to remove the blockage. Then, coronary bypass surgery may be the only option.
A new procedure, transmyocardial revascularization has shown promising results and may be appropriate for people who are high-risk candidates for a second bypass or angioplasty, people whose blockages are too diffuse to be treated with bypass alone, and some patients with heart transplants who develop atherosclerosis on the graft. It is, however, still considered experimental.
- Angioplasty. A catheter with a balloon tip is inserted into the coronary arteries. When the catheter reaches a narrowed segment, the balloon is inflated to flatten the plaque and widen the artery. In one newer variation, a rotating blade shaves the plaque into tiny particles, and in another, a laser beam vaporizes the plaque.
- Coronary bypass surgery. This procedure is reserved for severe cases of coronary blockage that can't be addressed by any other means. Segments of healthy blood vessels, either from the chest or leg, are used to bypass the severely narrowed parts of the coronary arteries. The result is greatly increased blood flow to the heart muscle, reducing risk of a heart attack.
- Transmyocardial revascularization. In this relatively new procedure, a laser cuts a series of channels in the heart muscle of a sick heart to increase blood flow. A surgeon makes an incision on the left side of the chest and inserts a laser into the chest cavity. With the laser, the surgeon shoots from 15 to 30 holes, each a millimeter in diameter, through the heart's left ventricle, in between heartbeats. (The laser is fired when the chamber is full of blood so the blood can protect the inside of the heart.) Then the surgeon seals the outer openings but lets the inner channels stay open, allowing oxygen-rich blood to flow through the heart muscle.
Some patients may require an electronic implant (pacemaker) to regulate heartbeat, and in severe cases of heart muscle damage, heart transplant may be indicated.
Appropriate Healthcare Setting
A heart attack is a medical emergency that requires immediate hospitalization.
Healthcare Professionals Who May Be Involved in Treatment
Many health professionals and cardiac specialists participate in managing this disorder, including:
- Family physicians
- General internists
- Cardiac surgeons
- Thoracic surgeons
Activity & Diet Recommendations
Post-attack, excitement, physical exertion, and emotional distress all place strain on the heart, making it work harder. Hospitals have cardiovascular rehabilitation programs that involve gradual increases in activity to strengthen your circulatory system.
The importance of diet in heart disease is well established and many experts recommend a low-fat, high-fiber diet for patients who have experienced a heart attack. Here are some general guidelines for healthier eating:
- Avoid foods high in saturated fats, such as meats, eggs, cheeses, and other dairy products
- Eat plenty of whole grains, breads, and cereals instead of white and refined grains
- Eat lots of fresh fruits and vegetables with meals and as snacks
- Eat legumes such as beans, peas, and lentils in soups and salads
Monitoring the Condition
Your family members should be educated about the signs of heart attack so they will be ready if subsequent heart attack occurs. Early recognition and treatment of a heart attack is important since the ultimate prognosis depends on how much heart muscle is dead and how impaired the heart function is after the heart attack. Close monitoring of heart function is strongly advised. Since monitoring methods should be tailored to your needs, consult your physician.
Heart attacks can cause serious complications:
- Congestive heart failure
- Cardiogenic shock (characterized by decreased pumping ability and low blood pressure)
- Heart muscle rupture
- Blot clots
- Inflammation of the membrane surrounding the heart (pericarditis)
- Irregular heartbeat (dysrhythmia)
- Back flow of blood from heart valves (mitral regurgitation)
- Bulge on the wall of the heart (ventricular aneurysm)
- Dressler's syndrome (also known as postmyocardial infarction syndrome, a specific type of inflammation of the membrane pericardium surrounding the heart that occurs weeks or months after a heart attack)
- Cardiac arrest
Quality of Life
Depending on the severity of your heart attack and the related coronary artery disease, available treatments range from lifestyle adjustments to major surgery. Which treatment is right for you depends on your individual situation. Making lifestyle changes such as improving diet, gradually increasing exercise, and reducing stress can improve your overall quality of life as well as reduce your risk for a future heart attack. And even if you opt for surgery, you'll still need to make lifestyle changes to address the underlying heart disease.
Considerations for Children and Adolescents
Young people without any risk factors for heart attack might have one if they use cocaine or methamphetamines.
Considerations for Older People
Older people are at particular risk for heart attack. Risk factors such as high blood pressure build up over time. Also, the coronary arteries nourishing the heart become thicker and lose their elasticity with age. Stress associated with loneliness or depression can also increase your risk for heart attack. Finally, your age may impact which course of treatment your doctor chooses.
- Vitamin E: Two landmark Harvard studies one involving men, the other, women showed that vitamin E (100 IU/day) substantially reduces the risk of heart attack. Compared with those who did not take the vitamin, the people who did suffered significantly percent fewer heart attacks 37% in men, 41% in women. Vitamin E is a powerful antioxidant that also helps treat heart disease.
- Vitamin C: A major antioxidant, Vitamin C also helps prevent and treat heart disease.
- B vitamins: The B vitamins help reduce blood levels of homocysteine, a recently identified risk factor for heart attack. Researchers in Northern Ireland gave supplemental B vitamins to 101 men with high homocysteine levels. Eight weeks later, their homocysteine levels had dropped 28%, significantly reducing their risk of heart attack. Nutrition experts suggest 3 mg of vitamin B-6 and 400 mcg of folic acid.
- Fish oil: you can get the omega-3 fatty acids found in cold-water fish without eating them if you take fish-oil supplements. In addition to preventing heart attack, fish oil also increases the effectiveness of angioplasty and coronary artery bypass surgery.
- Meditation is a key element of the Ornish program, and other studies also show its value. At the State University of New York, at Buffalo, researchers tested the exercise ability of 21 people with heart disease, and then taught them Transcendental Meditation (TM). Eight months later, they could exercise 15% more strenuously before experiencing chest pain, indicating a decreased risk of heart disease.
A great deal of research shows that the broad range of relaxation therapies helps prevent and treat heart disease. Practice whatever appeals to you: meditation, deep breathing, massage, hot baths, imagery/visualizations, progressive muscle relaxation, or self-hypnosis.
- Cherish your friends and family. The Ornish program includes a support group, since many studies show that social support helps prevent and treat heart disease. New York researchers followed more than 1,000 heart-attack survivors for four years. Among those who lived alone, 16 had a recurrence. But among those who lived with a spouse, the figure was only about half that.
- Garlic: Some experts believe that garlic reduces cholesterol and blood pressure, and it makes blood less likely to form the clots that can cause heart attacks. Commission E, the German panel of doctors, pharmacists, and herbalists that judges the safety and effectiveness of herbal medicines for the German government, recommends one to four garlic cloves a day.
- Willow bark: Doctors recommend low-dose aspirin to prevent the internal blood clots that trigger heart attacks. You can gain the same benefit from a cup of willow-bark tea. Willow bark contains salicin, aspirin's herbal precursor. A half-teaspoon of willow bark contains about 100 mg of salicin, enough to provide aspirin's benefits.
Last updated 23 May 2012
- Myocardial infarction
- Coronary thrombosis
- Coronary occlusion
- Ischemic heart disease
A heart attack is caused by the severe reduction or stoppage of the blood supply to part of the heart muscle. Heart attacks can occur when one of the arteries that supplies blood to the heart muscle is blocked by the buildup of plaque or a blood clot.
Other conditions that can cause a heart attack include the following:
- Coronary artery spasm: may cause artery to narrow, thus stopping blood flow to the heart. Spasm could be a result of smoking, emotional stress, or exposure to extreme cold.
- Inflammation of an artery (arteritis)
- Congenital (from birth) coronary abnormalities
- Carbon monoxide poisoning: carbon monoxide binds to red blood cells and prevents them from delivering oxygen to muscles and tissues.
Some of these factors do not directly cause a heart attack. However, they can be underlying causes that ultimately lead to a heart attack.
- Arteriosclerosis is an underlying cause because it causes arterial narrowing and promotes blood clot formation
- High cholesterol (hypercholesterolemia) is major risk factor for arteriosclerosis
- Heavy physical and psychological stress on inactive individuals
Drugs That Can Cause or Aggravate Heart Attacks
Illegal drugs like cocaine and methamphetamines may cause a heart attack.
There are many risk factors for heart attack:
- Diet high in fat and cholesterol
- Family history of coronary disease or cholesterol disorder
- High blood pressure
- Diabetes mellitus
- Elevated low-density lipoprotein (LDL or "bad" cholesterol)
- Decreased high-density lipoprotein (HDL or "good" cholesterol)
- Elevated levels of fats (triglycerides)
- Sustained psychological stress
- Increasing age
- Male gender
- Sedentary lifestyle
Symptoms & Diagnosis
A "silent" heart attack occurs without symptoms, while acute heart attacks are accompanied by the following signs and symptoms:
- Tightness, heaviness, pressure, and pain localized in the chest region below breastbone or down the left arm that last longer than 10 minutes or goes away and comes back
- Pain that spreads to the shoulders, neck, or arms
- Irregular beating of the heart (arrhythmia)
- Shortness of breath or choking sensation
- Cold sweat
- Dizziness, lightheadedness, or fainting
- Muscle weakness
- Nausea and vomiting
Conditions That May Be Mistaken for a Heart Attack
These conditions also cause chest pain and sometimes shortness of breath, which may be confused with a heart attack:
- Unstable angina pectoris: chest pain caused by lack of oxygenated blood flow to the heart that begins for no apparent reason.
- Gastrointestinal disorders such as peptic ulcer, indigestion, hiatus hernia, gallbladder disease, and spasms or inflammation of the esophagus
- Aortic aneurysm: injury of the tissue in the wall of aorta (the major artery carrying blood out of the heart)
- Chronic shortness of breath (dyspnea)
- Blood clot in the lung, pneumonia, or pleurisy
- Inflammation of the membrane around the heart (pericarditis)
- Inflammation of or damage to the ribs
- Disease of the spinal nerve roots (radiculopathy)
- Psychological disorders due to panic or anxiety
- Cervical or thoracic spine disease
How Are Heart Attacks Diagnosed?
Diagnosis is made on the basis of a physical examination, laboratory results, and special tests and imaging procedures.
Laboratory tests for confirming a heart attack should be done within hours following the attack:
- Creatine phosphokinase is an enzyme that is excreted by dying heart muscle. This enzyme is the most specific indicator of heart muscle death.
- Troponin T and I are cardiac muscle proteins that usually have very low blood levels, but increase substantially within several hours (on average four to six hours) of muscle damage. Levels peak at 10 to 24 hours and can be detected for a week or more after. Elevated levels of troponin can also be due to skeletal muscle damage or severe ischemia (a usually temporary oxygen deficiency in a part of the body).
Special tests are performed to confirm abnormalities of cardiac activity:
- Electrocardiogram (ECG or EKG) measures electrical activity of the heart, which is almost always abnormal following a heart attack.
These techniques provide images of the damaged muscle, though sensitivity varies with severity of the heart attack:
- Chest X-ray: shows signs of congestive heart failure
- Echocardiogram: uses ultrasound to create a moving image of your heart and allows assessment of cardiac function
- Injection of radioisotope thallium: distinguishes "cold spots," or damaged heart muscle areas, but does not distinguish new damage from old damage
- Technetium-99m pyrophosphate scintigraphy: a radiotracer reacts with calcium in the dead heart muscle, providing an image of the site of attack
Self care & Prevention
Preventing Heart Attacks
- If you smoke, quit. Smoking is a major risk factor for heart attack, and quitting quickly reduces your risk.
- Exercise regularly. An enormous amount of research shows that physical activity reduces risk of heart attack. In one study, Harvard researchers analyzed the results of more than a dozen studies that correlated exercise and risk of death from heart attack. Compared with sedentary individuals, people who got regular exercise had just half the risk. Exercise is also a standard part of post-heart-attack rehabilitation.
- Know the signs of heart attack. Knowing the warning signs of a heart attack can help you and your family members plan to act immediately. While you may not experience all these symptoms, getting to an emergency room at the first sign of warning is critical to survival and may help prevent more serious injury. Unless you suffer from a massive heart attack and fall unconscious, you will most likely experience some of the following signs:
- Pressure, squeezing, or pain sensation in the center of your chest, lasting for a few minutes
- Pain beginning in the chest and spreading to your shoulders, neck, and down your arms
- Lightheadedness, fainting, sweating, nausea, or shortness of breath
It's also important to have a plan of action once symptoms begin. This can reduce the time in getting medical care and further increase your chances of survival.
- Reduce stress. Stress increases blood pressure, which may put you at greater risk for a heart attack.
- Eat a low-fat diet. An ultra low-fat diet is a key element of the only program ever shown to reverse coronary artery disease, the underlying cause of heart attacks. Pioneered by Dean Ornish, M.D., of the Preventive Medicine Research Institute in Sausalito, Calif., the program has five components:
- Vegetarian diet containing just 10% fat (compared to the average American's 35%)
- Daily exercise, like walking
- Weekly support-group meetings
In a series of three landmark studies, Ornish showed that people who embrace his program enjoy progressively increasing blood flow through their coronary arteries, a feat that drugs and surgery cannot match. As coronary artery blood flow increases, heart attack risk decreases.
- Eat more plant foods. Even if you don't adopt the entire Ornish program, it's a good idea to limit meats and eat more plant foods, which include fruits, vegetables, beans, and whole grains. In one study, Harvard researchers followed 44,000 middle-aged men for six years. As the men's plant-food consumption increased, their risk of heart disease decreased. Compared with those who ate the fewest plant foods, those who ate the most enjoyed substantial protection from heart attacks. Plant foods are high in antioxidant nutrients, which prevent the cell damage at the root of heart disease.
Plant foods are central to the "Mediterranean diet" of people in Spain, Italy, and Greece. People there consume a good deal more fat than the Ornish-program limit, but it's mostly monounsaturated olive oil, the heart-healthiest fat, as opposed to the saturated fat found in meat, the kind that leads to heart disease. Several studies show that the Mediterranean diet helps prevent heart disease. And if you've survived a heart attack, this diet can prevent a recurrence. In one study, French researchers told 605 heart-attack survivors to eat either a diet heavier in saturated fat or a Mediterranean-style diet. During five years of follow-up, the Mediterranean group had 72% fewer second heart attacks.
- Try drinking tea. Several recent studies have shown that, like plant foods, tea is high in the antioxidants that prevent heart attack.
- Eat more cold-water fish. Eating cold-water fish, notably salmon, may also help prevent and treat heart disease. Cold-water fish are high in omega-3 fatty acids, which help prevent the arterial damage that leads to heart attack.
- Drink a little red wine. Many studies show that modest alcohol consumption (about one drink a day) raises HDL (or "good") cholesterol, the kind that reduces risk of heart attack. In addition, red wine contains extra antioxidants that further reduce risk. Some people shouldn't drink at all, including current or former alcoholics, those with a family history of alcoholism, pregnant women, and people with liver disease. But if you can drink, a little alcohol, especially red wine, can help prevent heart disease.