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According to the Centers for Disease Control and Prevention, more than 800,000 Americans suffer heart attacks each year. This translates to one heart attack approximately every 40 seconds. Experts from Emory Healthcare estimate that 550,000 new cases of heart failure are diagnosed each year in the United States. Myocarditis, an inflammation of the heart muscle, affects approximately 1.5 million people worldwide each year.
This guide provides a comprehensive overview of the troponin blood test, including why it’s used and what the results might mean. It also provides information on three conditions that can cause elevated troponin levels: heart attack, congestive heart failure, and myocarditis.
The purpose of the troponin test is to determine if an individual has an elevated troponin level. Because troponin is stored in the heart muscle and doesn’t normally circulate in the blood, it usually doesn’t show up on a blood test unless the heart has sustained some kind of damage. Therefore, the troponin blood test is useful for diagnosing a heart attack, congestive heart failure, and other heart conditions.
According to MedlinePlus, the troponin test should be ordered when an individual presents in the emergency room with chest pain or other signs of a heart attack. The troponin test should also be ordered when an individual has signs of congestive heart failure, such as shortness of breath or swelling in the legs, or myocarditis.
Once the heart is damaged, troponin levels steadily increase until they level off and then return to normal over several days or weeks. Therefore, the test should be performed three times in a 12-hour period, which means three blood samples are required to determine if an individual’s troponin level is truly normal.
No special preparation is required for the troponin test.
Heart attack, also known as myocardial infarction, occurs when something blocks blood from flowing to part of the heart, which starves the heart muscle of oxygen. If an individual does not seek medical attention right away, the affected portion of the heart muscle starts to die. Heart attacks can occur for many reasons, but one of the most common is a form of heart disease that causes the blood vessels to narrow. This is known as ischemic heart disease. In some people, cholesterol, calcium, and other substances combine to form plaque, a substance that can build up on the walls of the arteries. If some of the plaque breaks away, a clot may form, restricting blood flow and preventing an adequate amount of oxygen from reaching every part of the heart muscle. Heart attacks may also be caused by abnormal heart rhythms, heart failure, or a spasm of one of the coronary arteries.
According to the American Heart Association, some of the most significant risk factors for heart attack are smoking, high cholesterol, hypertension (high blood pressure), obesity/excess weight, diabetes, and a lack of exercise. People who have high levels of stress, eat a lot of red meat or sweets, or consume more than moderate amounts of alcohol also have a higher risk of having a heart attack. Many of these risk factors can be modified by making positive lifestyle changes. For example, quitting smoking, getting more exercise, and controlling diabetes can reduce an individual’s risk of having a heart attack.
Unfortunately, a few risk factors can’t be altered. These are known as non-modifiable risk factors because they can’t be changed no matter what an individual does. African Americans, Hawaiians, American Indians, and certain groups of Asian Americans have a heightened risk of having a heart attack. So do men, older people, and people whose parents had or are currently living with heart disease. If a heart attack occurs, some of the most common symptoms include chest pain, shortness of breath, and discomfort in the upper body. Heart attacks may also cause sweating, dizziness, nausea and vomiting, and fatigue.
In people with congestive heart failure, the heart can’t pump the right amount of blood. When the heart can’t pump enough blood to other parts of the body, blood can back up into the lungs, causing fatigue and shortness of breath. Fluid can also back up into the lungs, causing swelling in the legs, ankles, or feet. Many conditions can increase the risk for heart failure, including a history of heart attack, coronary artery disease, defects in one of the heart valves, cardiomyopathy, high blood pressure, diabetes, and severe lung disease. Obesity and sleep apnea are also risk factors for this condition.
The signs and symptoms of heart failure include shortness of breath, chronic cough, swelling, fatigue, wheezing, nausea, loss of appetite, increased heart rate, and confusion. Most of these symptoms occur due to the buildup of blood and fluid in the heart and lungs. For example, when the digestive system doesn’t get enough blood, digestion is impaired, which can cause an upset stomach.
Myocarditis is an inflammation of the heart muscle caused by some type of infection. When an infectious organism invades the heart muscle, it quickly begins to replicate. This replication process damages the heart muscle. The immune system tries to fight off the infection, which can cause additional damage. Myocarditis is usually diagnosed based on the results of blood tests, X-rays, and an ultrasound of the heart. A biopsy of the heart muscle can also help determine which organism is responsible for the underlying infection.
Some people with myocarditis don’t have any symptoms, preventing them from receiving a diagnosis right away. The most common signs and symptoms of this condition include fatigue, shortness of breath, lightheadedness, heart palpitations, swelling in the lower extremities, chest pain, sudden loss of consciousness, and chest pressure.
Troponin is found in all striated muscles, including the heart muscle and skeletal muscles. Striated means that the muscle tissue looks like it has stripes when it’s viewed under a microscope. Although all striated muscles contain troponin, the troponin that comes from the heart muscle doesn’t look the same as the troponin that comes from skeletal muscles. Therefore, the troponin test is highly sensitive for identifying heart muscle damage.
Once the laboratory receives the individual’s first blood sample, lab personnel use a method known as electrochemiluminescence immunoassay to determine if any cardiac troponin is present. If it is, it’s highly likely that the heart muscle has sustained some type of damage. The test is repeated twice to confirm that the individual’s troponin level has not increased since the first test was performed.
The treatment methods used for heart attack depend on the individual’s symptoms, the extent of the heart damage, and other factors. For example, health care providers often make treatment decisions based on whether the individual suffered a STEMI or an NSTEMI. STEMI, which stands for ST-elevation myocardial infarction, occurs when there’s a complete blockage of one of the coronary arteries. NSTEMI, or non-ST-elevation myocardial infarction, occurs when there’s a partial blockage. Some of the most common treatment options for heart attack include medications, medical procedures, and surgery. Delaying treatment can lead to poor outcomes for someone suffering a heart attack, so it’s important to call 911 right away if chest pain, shortness of breath, or other signs of a heart attack occur.
Upon arriving in the emergency room, an individual with a suspected heart attack may be given aspirin, which thins the blood by preventing platelets from sticking together. Platelets are cell fragments that aid in blood clotting. After discharge from the hospital, someone who’s had a heart attack may have to take several medications to control heart rate, reduce blood pressure, and lower high levels of cholesterol. In addition to aspirin, an individual with a history of heart attacks may also have to take clopidogrel or another blood thinner to prevent additional heart attacks.
Medical procedures used to treat heart attacks include angioplasty, stenting, and atherectomy. Angioplasty is a procedure in which a tube is advanced into the blocked artery. The tube has a deflated balloon attached to it; once the tube has reached its destination, the balloon is inflated to relieve the blockage. Stenting involves inserting a small tube made of wire mesh (a stent) into the blocked artery. This procedure takes place during an angioplasty. During an atherectomy, a catheter is inserted into the blocked artery. The tip of the catheter has a shaver attached to it; this shaver is used to remove plaque from the walls of the artery.
Bypass surgery may be performed if an individual is a poor candidate for any of these less-invasive procedures. During bypass surgery, the surgeon removes a vessel from the chest or one of the limbs and uses it to redirect blood around the blocked artery. In other words, the blood “bypasses” the artery, giving the procedure its name.
Treatment options for heart failure include medications, medical devices, lifestyle changes, and surgery. Medications are usually prescribed to lower blood pressure, control the individual’s heart rate, and prevent excess fluid from accumulating in the legs, ankles, and feet. Some people with congestive heart failure also have to take medications to lower their cholesterol or prevent blood clots.
Medical devices can be used to correct abnormal heart rhythms or help the heart pump more blood with each beat. An implantable defibrillator delivers electrical shocks to the heart any time it detects a dangerous heart rhythm. Left ventricular assist devices are used to help the left ventricle pump more blood. These devices can help prevent further damage to the heart while an individual awaits a heart transplant. Cardiac resynchronization therapy involves implanting a pacemaker to help the ventricle contract and relax in a normal rhythm. Angioplasty or heart transplant may also be necessary for someone who has congestive heart failure. During a heart transplant, the individual is connected to a bypass machine so that the damaged heart can be removed and replaced with a healthy heart from a donor.
Lifestyle changes can help relieve the symptoms of congestive heart failure and prevent it from progressing. Individuals who are overweight or obese will be advised to lose excess weight. Quitting smoking, limiting alcohol intake, and limiting caffeine intake can all help an individual with heart failure keep the symptoms under control. Because heart failure causes fluid and blood to back up into the lungs, some individuals with this condition have to limit the amount of fluid they consume each day, whether it’s in the form of beverages or foods that turn into liquid after they are consumed. Examples include ice cream, gelatin, and ice pops. Reducing stress, eating nutritious foods, and getting some physical activity each day are also important for managing heart failure.
The right treatment for myocarditis depends on the individual’s health status, how severe the condition is, and other factors. For people with mild myocarditis caused by a virus, avoiding strenuous activities, alcohol, and tobacco may be all that’s needed. If myocarditis is caused by a bacterial infection, antibiotics can kill the bacteria and make the symptoms go away. In cases of serious myocarditis, an individual is usually hospitalized and monitored closely by health care providers. Treatment options include oxygen therapy, insertion of a pacemaker to control abnormal heart rhythms, non-steroidal anti-inflammatory drugs (NSAIDs) or steroids to relieve inflammation and pain, and medications to treat the symptoms of heart failure.
A normal troponin level ranges from 0 to 0.4 nanograms per milliliter (ng/mL).
The troponin test has minimal risks. It’s possible to faint while having blood drawn, or to feel dizzy or lightheaded. Any time a needle pierces the skin, there’s also a risk of infection, although it’s a slight one.
An individual with chest pain should call 911 immediately and ask for an ambulance. It could be dangerous to drive to the hospital, as an individual with chest pain may be having a heart attack, which could cause loss of consciousness and lead to an auto accident. Additionally, ambulances are equipped with life-saving equipment and medications. If the individual’s status worsens during the ambulance ride, the paramedics can administer CPR, use a defibrillator to restart the heart, or administer medications to prevent additional complications.
In people with heart failure, the heart doesn’t pump enough blood, but that doesn’t mean it has completely stopped working.
If an individual arrives at the hospital within minutes of experiencing chest pain or other heart attack symptoms, it’s possible the first troponin test will be normal even if the individual is having a heart attack. Doing the test two more times helps identify elevated troponin levels in someone whose initial test result was normal.
|MedlinePlus||www.medlineplus.gov||MedlinePlus provides information on a variety of tests used to diagnose heart attacks and other heart conditions.|
|National Heart, Lung, and Blood Institute||www.nhlbi.nih.gov||The NHLBI offers valuable resources on conditions that affect the heart and lungs.|
|American Heart Association||www.heart.org||Learn more about heart attack and heart failure.|
|The Myocarditis Foundation||www.myocarditisfoundation.org||The Myocarditis Foundation offers educational resources to help people understand myocarditis.|
|The Heart Foundation||www.theheartfoundation.org||The Heart Foundation funds research into heart conditions and offers educational materials for patients and their families.|
|The National Institute on Aging||www.nia.nih.gov||The NIA provides educational resources for older people interested in learning more about heart disease and other diseases that affect the elderly.|