Acute coronary syndromes result from a sudden blockage in a coronary artery. This blockage causes unstable angina or a heart attack (myocardial infarction), depending on the location and amount of blockage. A heart attack is death of heart tissue due to lack of blood supply. Show
In the United States, more than 900,000 people have a heart attack or sudden cardiac death each year. And acute coronary syndromes cause almost 400,000 deaths each year. Almost all of them have underlying coronary artery disease and about two thirds of them are men. Uncommonly, a heart attack results when a clot forms in the heart itself, breaks away, and lodges in a coronary artery. Another uncommon cause is a spasm of a coronary artery that stops blood flow. Spasms may be caused by drugs such as cocaine. Sometimes the cause is unknown. Doctors classify acute coronary syndromes based on
The classification is important because treatments differ depending on the specific acute coronary syndrome. The classification consists of unstable angina and two types of heart attack.
Symptoms of Acute Coronary SyndromesSymptoms of the acute coronary syndromes are similar, and it is usually impossible to distinguish the syndromes based on symptoms alone. Symptoms of unstable angina are the same as those of angina pectoris Symptoms Angina is temporary chest pain or a sensation of pressure that occurs while the heart muscle is not receiving enough oxygen. A person with angina usually has discomfort or pressure beneath the... read more —people typically have intermittent pressure, or an ache beneath the breastbone (sternum). People often interpret the sensation as discomfort or heaviness rather than pain. Discomfort also may occur in either shoulder or down the inside of either arm, through the back, and in the throat, jaw, or teeth. However, in people with unstable angina, the pattern changes. People experience more frequent or more severe episodes of angina, or episodes occur at rest or after less physical exertion. About two of three people who have heart attacks experience unstable angina, shortness of breath, or fatigue a few days or weeks beforehand. Such a change in the pattern of chest pain discomfort may culminate in a heart attack. With a heart attack, the most recognizable symptom is usually pain in the middle of the chest that may spread to the back, jaw, or left arm. Less often, the pain spreads to the right arm. The pain may occur in one or more of these places and not in the chest at all. The pain of a heart attack is similar to the pain of angina but is generally more severe, lasts longer, and is not relieved by rest or nitroglycerin. Less often, pain is felt in the abdomen, where it may be mistaken for indigestion, especially because belching may bring partial or temporary relief. For unknown reasons, women often have different symptoms, sometimes described as atypical chest pain, that are less likely to be accurately diagnosed as a heart problem. Other symptoms include a feeling of faintness or actually fainting, sudden heavy sweating, nausea, shortness of breath, and a heavy pounding of the heart (palpitations). During a heart attack, a person may become restless, sweaty, and anxious and may experience a sense of impending doom. The lips, hands, or feet may turn slightly blue. Older people may have unusual symptoms. In many, the most obvious symptom is breathlessness. Symptoms may resemble those of a stomach upset or a stroke. Older people may become disoriented. Nonetheless, about two thirds of older people have chest pain, as do younger people. Older people, especially women, often take longer than younger people to admit they are ill or to seek medical help. Despite all the possible symptoms, as many as one of five people who have a heart attack have only mild symptoms or none at all. Such a silent heart attack may be recognized only when ECG is routinely done some time afterward. During the early hours of a heart attack, heart murmurs and other abnormal heart sounds may be heard through a stethoscope. People who have a heart attack may also have
complications
Complications of an Acute Coronary Syndrome The heart muscle needs a constant supply of oxygen-rich blood. The coronary arteries, which branch off the aorta just after it leaves the heart, deliver this blood. An acute coronary syndrome... read more that can be long-lasting. The
complications of acute coronary syndromes depend on how much of the heart muscle is damaged which is a direct result of where a coronary artery was blocked and how long this artery was blocked. If the blockage affects a large amount of heart muscle, the heart will not pump effectively and can become enlarged, possibly leading to
heart failure Heart Failure (HF)
Heart failure is a disorder in which the heart is unable to keep up with the demands of the body, leading to reduced blood flow, back-up (congestion) of blood in the veins and lungs, and/or... read more
Whenever a man over age about 30 or a woman over age about 40 reports
chest pain
Chest Pain Chest pain is a very common complaint. Pain may be sharp or dull, although some people with a chest disorder describe their sensation as discomfort, tightness, pressure, gas, burning, or aching... read more , doctors usually consider the possibility of an acute coronary syndrome.
But several other conditions can cause similar pain, such as pneumonia
Overview of Pneumonia Pneumonia is an infection of the small air sacs of the lungs (alveoli) and the tissues around them. Pneumonia is one of the most common causes of death worldwide. Often, pneumonia is the final... read more
ECG
Electrocardiography Electrocardiography (ECG) is a quick, simple, painless procedure in which the heart’s electrical impulses are amplified and recorded. This record, the electrocardiogram (also known as an ECG)... read more
Measuring levels of certain substances (called cardiac markers) in the blood also helps doctors diagnose acute coronary syndromes. These substances are normally found in heart muscle but are released into the blood only when heart muscle is damaged or dead. Most commonly measured are heart muscle proteins called troponin I and troponin T and an enzyme called CK-MB (creatinine kinase, myocardial band subunit). Levels in the blood are elevated within 6 hours of a heart attack and remain elevated for several days. Levels of cardiac markers are usually measured when the person is admitted to the hospital and at 6- to 12-hour intervals for the next 24 hours. Many people who have unstable angina go on to have a heart attack within about 3 months. The most dangerous time for someone who is having a heart attack is during the first few hours and
before they go to a hospital. During this period, up to 20 to 30 percent of people with a heart attack may die, so it is critical to seek medical attention immediately when people suspect they are having a heart attack. Most people who survive for a few days after a heart attack can expect a full recovery, but about 10% die within a year. Most deaths occur in the first 3 or 4 months, typically in people who continue to have angina,
abnormal heart rhythms
Overview of Abnormal Heart Rhythms Abnormal heart rhythms (arrhythmias) are sequences of heartbeats that are irregular, too fast, too slow, or conducted via an abnormal electrical pathway through the heart. Heart disorders are... read more
Older people are more likely to die after a heart attack and to have complications, such as heart failure. The prognosis for smaller people is worse than that for larger people. This finding may help explain why the prognosis for women who have had a heart attack is, on average, worse than that for men. Women also tend to be older and to have more serious disorders when they have a heart attack. Also, they tend to wait longer after a heart attack to go to the hospital than do men. For people who have had a heart attack, doctors recommend taking one baby aspirin, one half of an adult aspirin, or one full adult aspirin daily. Because aspirin prevents platelets from forming clots, it reduces the risk of death and the risk of a second heart attack by 15 to 30%. People with an allergy to aspirin may take clopidogrel instead. Aspirin is not currently recommended for prevention of acute coronary syndrome in people who have not already had a heart attack. Taking lipid-lowering drugs will reduce the risk of death after a heart attack. People at high risk (especially obese people with diabetes) who have not yet had a heart attack or stroke may benefit from lipid-lowering drugs. Angiotensin-converting enzyme (ACE) inhibitors, such as captopril, enalapril, perindopril erbumine, trandolapril, lisinopril, and ramipril, are often prescribed after a heart attack. These drugs help prevent death and the development of heart failure, particularly in people who have had a massive heart attack or who develop heart failure. People should also make changes in their lifestyle. They should eat a low-fat diet and increase the amount of exercise they get. People who have high blood pressure or diabetes should try to keep those disorders under control. People who smoke should quit.
Acute coronary syndromes are medical emergencies. Half of deaths due to a heart attack occur in the first 3 or 4 hours after symptoms begin. The sooner treatment begins, the better the chances of survival. Anyone having symptoms that might indicate an acute coronary syndrome should obtain prompt medical attention. Prompt transportation to a hospital’s emergency department by an ambulance with trained personnel may save the person’s life. Trying to contact the person’s doctor, relatives, friends, or neighbors is a dangerous waste of time. Did You Know...
People who may be having a heart attack are usually admitted to a hospital that has a cardiac care unit. Heart rhythm, blood pressure, and the amount of oxygen in the blood are closely monitored so that heart damage can be assessed. Nurses in these units are specially trained to care for people with heart problems and to handle heart emergencies. Often, oxygen is given through nasal prongs or a face mask. Providing more oxygen to the heart helps keep heart tissue damage to a minimum. If no
complications
Complications of an Acute Coronary Syndrome The heart muscle needs a constant supply of oxygen-rich blood. The coronary arteries, which branch off the aorta just after it leaves the heart, deliver this blood. An acute coronary syndrome... read more occur during the first few
days, most people can safely leave the hospital within a few more days. If complications such as abnormal heart rhythms
Overview of Abnormal Heart Rhythms Abnormal heart rhythms (arrhythmias) are sequences of heartbeats that are irregular, too fast, too slow, or conducted via an abnormal electrical pathway through the heart. Heart disorders are... read more
The most important issue in the early part of treatment of a heart attack is to get to medical attention quickly so doctors can attempt to restore blood flow in the affected artery. People who think they may be having a heart attack should chew an aspirin tablet immediately after calling an ambulance. If aspirin is not taken at home or given by emergency personnel, it is immediately given at the hospital. This therapy improves the chances of survival by reducing the size of the clot (if present) in the coronary artery. People with an allergy to aspirin may be given clopidogrel, ticlopidine, or ticagrelor instead. Some people are given both aspirin and clopidogrel, ticlopidine, or ticagrelor. People are given drugs to prevent the formation of blood clots, to reduce anxiety, and to reduce the size of the heart. People may need to take these drugs for some time after they have recovered from a heart attack. Drugs are used to reduce the heart's workload during and after a heart attack. Because decreasing the heart’s workload also helps limit tissue damage, a beta-blocker is usually given to slow the heart rate. Slowing the rate enables the heart to work less hard and reduces the area of damaged tissue. Most people are also given an anticoagulant drug, such as heparin, to help prevent the formation of additional blood clots. Most people are given nitroglycerin, which relieves pain by reducing the workload of the heart and possibly by dilating arteries. Usually, it is first given under the tongue, then intravenously. Occasionally, when nitroglycerine cannot be used or is ineffective, doctors give morphine to reduce discomfort and anxiety. The decision on the timing and method of opening a blocked coronary artery depends on the type of acute coronary syndrome and on how quickly the person got to the hospital. There are several ways to open blocked coronary arteries:
In people who have an ST-segment elevation MI, immediately clearing the coronary artery blockage saves heart tissue and improves survival. Doctors try to clear the blockage within 90 minutes after the person arrives at the hospital. Because the sooner the artery is cleared the better the outcome, the method of clearing is probably not as important as the timing. Clot-dissolving drugs (also called thrombolytic or fibrinolytic drugs—see table
Drugs Used to Treat Coronary Artery Disease
Drugs Used to Treat Coronary Artery Disease* Because thrombolytic drugs can cause bleeding, they are not usually given to people who have bleeding in the digestive tract, who have severe high blood pressure, who have recently had a stroke, or who have had surgery during the month before the heart attack. Older people who do not have any of these conditions can be safely given a thrombolytic drug. People who have a non-ST-segment elevation MI or unstable angina do not usually benefit from immediate PCI or thrombolytic drugs. However, doctors usually do PCI within the first day or two of hospitalization. If the person’s symptoms worsen or certain complications develop, doctors may do PCI earlier. Because physical exertion, emotional distress, and excitement stress the heart and make it work harder, a person who has just had a heart attack should stay in bed for a short while and stay in a quiet room for a few days. Visitors are usually limited to family members and close friends. Watching television may be permitted if the programs do not cause stress. Stool softeners and gentle laxatives may be used to prevent constipation, so that the person does not have to strain. If the person cannot pass urine or if the doctors and nurses need to keep track of the precise amount of urine produced, a urinary catheter is used. For severe nervousness (which can stress the heart), a mild antianxiety drug (for example, a benzodiazepine such as lorazepam) may be prescribed. To deal with mild depression and denial of illness, which are common after acute coronary syndromes, people are encouraged to talk about their feelings with doctors, nurses, social workers, and their family members and friends. Some people require an antidepressant. After about 2 to 4 days in the hospital, people who have had an uncomplicated heart attack and successful PCI are usually discharged. Other people may require a longer stay. Nitroglycerin, aspirin, and sometimes clopidogrel, a beta-blocker, an angiotensin-converting enzyme (ACE) inhibitor, and a
lipid-lowering drug
Lipid-lowering drugs Dyslipidemia is a high level of lipids (cholesterol, triglycerides, or both) or a low high-density lipoprotein (HDL) cholesterol level. Lifestyle, genetics, disorders (such as low thyroid hormone... read more Cardiac rehabilitation Rehabilitation for Heart Disorders Cardiac rehabilitation is useful for some people who have had a recent heart attack, have heart failure or coronary artery disease that has recently developed or suddenly worsened, or had heart... read more , an important part of recovery, begins in the hospital. Remaining in bed for longer than 2 or 3 days leads to physical deconditioning and sometimes to depression and a sense of helplessness. Barring complications, people who have had a heart attack can usually progress to sitting in a chair, passive exercise, use of a commode chair, and reading on the first day. By the second or third day, people are encouraged to walk to the bathroom and engage in nonstressful activities, and they can do more activities each day. If everything goes well, people are usually back to their normal activities within about 6 weeks. Participation in a regular exercise program consistent with the person’s age and heart health is beneficial. What leads up to myocardial infarction?Myocardial ischemia occurs when blood flow to the heart muscle (myocardium) is obstructed by a partial or complete blockage of a coronary artery by a buildup of plaques (atherosclerosis). If the plaques rupture, you can have a heart attack (myocardial infarction).
Which of the following is the most common complication of myocardial infarction?Ventricular free wall rupture. VFWR is the most serious complication of AMI. VFWR is usually associated with large transmural infarctions and antecedent infarct expansion. It is the most common cause of death, second only to LV failure, and it accounts for 15-30% of the deaths associated with AMI.
What is the most common precipitating event for myocardial infarction?A sudden change in position is the most frequent potential trigger, typically occurring the morning after awakening from sleep.
What are the 3 most common complications of an MI?The most commonly encountered mechanical complications are acute mitral regurgitation secondary to papillary muscle rupture, ventricular septal defect, pseudoaneurysm, and free wall rupture; each complication is associated with a significant risk of morbidity, mortality, and hospital resource utilization.
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