Acute Coronary Syndrome and Heart Attack
Can bone and muscle diseases and disorders cause pain like that of a heart attack?
Injured chest muscles or ribs, particularly a broken (fractured) rib due to any number of injuries, can produce severe pain that may resemble pain from a heart attack. However, as in treating most other mimicking disorders, your doctor would be able to arrive at a diagnosis by asking you about your symptoms and by chest x-ray examination and other diagnostic tests.
Sore muscles due to vigorous physical activities, particularly competitive sports, also may cause pain in the chest, shoulders, and arms. Severe arthritis of the ribs may cause pain, sometimes similar to cardiac pain.
Another disorder that can imitate the pain of a heart attack is shingles (herpes zoster in medical terms). A virus (the same virus that produces chicken pox) causes shingles, which would produce intense pain and a band of blisters on your back around your chest wall(along the nerve distribution). At times, it can seem like a heart attack, but the diagnosis is obvious to a doctor in most cases.
DIAGNOSING AHEART ATTACK
What is an electrocardiogram, and what is its diagnostic value?
An electrocardiogram (ECG or EKG) is the most important first test used to diagnose a heart attack. An ECG records the electrical activity of your heart through wires and electrodes attached to the skin of your arms, legs, and chest wall. Your heart’s sinus node generates electrical impulses that are recorded as wave patterns displayed on a monitor or are printed on paper. Since damaged heart muscle fails to conduct electrical impulses normally, the ECG may show an old (prior) heart attack or an acute (new) heart attack in progress.
The most important wave pattern in diagnosing a heart attack is the large Q wave and the S-T segment elevation (ECG segment from the endpoint of the QRS complex to the beginning of the T wave; When the entire thickness of your heart muscle is damaged, a large Q wave is shown on the ECG (then it’s called a Q-wave myocardial infarction or a Q-wave heart attack). On the other hand, the term non-Q-wave MI is used when the ECG shows only an S-T segment change without the large Q wave. A non-Q-wave MI occurs when primarily the inner layer of your heart muscle is damaged. When the ECG displays a large Q wave with the S-T segment elevation in a heart attack, the heart attack is considered to be acute, and the damage is in progress. As mentioned, a heart attack is considered to be old when there is a Q wave with no S-T segment elevation. Clinically, a Q-wave heart attack is said to be more serious than a non-Q-wave heart attack.
The ECG is also very important for diagnosing a variety of abnormal heart rhythms (cardiac arrhythmias; In addition, the ECG provides extremely important information to your doctor in ruling out the diagnosis of a heart attack in dealing with various diseases and disorders that produce chest pain resembling that of a heart attack.
What blood tests are available for diagnosing a heart attack?
Certain enzymes (protein molecules) normally found in the heart muscle leak out into the bloodstream when a heart attack damages the heart muscle. A blood test will show increased levels of these enzymes in the blood. (The blood test used most commonly to look for the presence of various enzymes is the measurement of CK-MB: creatine kinase myocardial band.
(Our discussion here doesn’t go into the technical explanation of the CK-MB marker.) Although CKMB has been standard marker, it’s not very accurate, since elevated levels can be found also in people without heart damage. Other enzymes may include troponins, myoglobin, and C-reactive protein.
Who needs a stress test? What is its diagnostic value?
Several different kinds of stress tests are used, but the test used most commonly is the treadmill stress test. Obviously, a stress test should not be performed when a heart attack is acute (i.e., in progress). The stress test is usually performed for screening or as a first-line evaluation of symptoms, particularly those of chest pain. This test evaluates how your heart and blood vessels respond to exertion; the results may indicate whether your chest pain is due to a coronary artery disease (CAD), particularly angina. A stress test is essential for evaluating chest pain and marked shortness of breath, particularly that which is related to physical exercise. However, your doctor first would ensure against the probability of an acute (new) heart attack. The test is especially an important screening and diagnostic test for anyone with one or more coronary risk factors, even for those without a history of heart symptoms, including chest pain.
In a treadmill exercise stress test, you would walk on a motor-driven treadmill while a doctor monitors and records your ECG picture and your blood pressure (BP). During the test, your heart workload progressively increases until any significant symptom (e.g., chest pain) or some ECG abnormality develops. Every 3 minutes, a faster speed and an increase in the elevation (or slope) of the treadmill progressively increases your heart’s workload. If you are unable to walk on a treadmill, doctors can provide you with other forms of exercise, such as pedaling a stationary bicycle or performing arm exercises and various pharmacologic (nonexercise) stress tests. People with arthritis or other problems with walking can use such nonexercise stress tests as adenosine, dipyridamole, or dobutamine. These pharmacologic agents “stress” your heart (in the good sense of that term) by mimicking the effects of physical exercise. Imaging tests provide useful additional diagnostic information by producing pictures of your heart during and after physical exercise or pharmacologic stress testing.
Imaging tests may be used alone or may clarify the results of previous stress tests without using imaging.
Term:
Stress test – test that evaluates how the heart and blood vessels respond to exertion and may allow diagnosis of coronary artery disease; may be performed using a treadmill or various chemicals (e.g.,dobutamine, adenosine).
