American Medical Association Family Medical Guide - American Medical Association [327]
Another heart muscle enzyme, called CK-MB, is also released into the blood after a heart attack. Elevated CK-MB levels appear within 6 hours of a heart attack and last for 36 to 48 hours. CK-MB levels usually are measured soon after a person is admitted to the hospital and at 6- to 8-hour intervals over the next 24 hours.
If you have had or are having a heart attack, treatment will begin immediately. The doctor may order additional tests, such as a chest X-ray (see page 109), an echocardiogram (see page 561), a radionuclide scan (see page 114), or a coronary angiogram (see page 561). A chest X-ray allows the doctor to evaluate the size and shape of your heart and coronary arteries. An echocardiogram may show damage to the left ventricle (the pumping chamber of the heart). A radionuclide scan may show reduced blood flow to a specific area of the heart that has been damaged by a heart attack. A coronary angiogram can show if the arteries that supply blood to the heart are narrowed or blocked.
Before you leave the hospital, you will probably have tests to evaluate the extent of any underlying heart disease. These tests—an ECG and, perhaps, a coronary angiogram or an echocardiogram—will help the doctor accurately determine the extent of the damage to the heart muscle and whether any narrowed or blocked sections in the coronary arteries might need to be opened with surgery. The severity of the disease will determine if surgery is necessary.
Treatment
The sooner treatment for a heart attack begins, the better your chances of survival. Treatment may include medication, surgery, or both, depending on your overall health and the amount of damage to the heart muscle.
Medication
You may be given nitroglycerin to improve blood flow to and from your heart and to relieve pain. If your pain is severe, you may be given a strong pain reliever such as morphine. You will probably be given antiplatelet drugs (such as aspirin) or anticoagulant drugs (such as heparin) to help prevent blood clots from forming again in the coronary arteries or new clots from forming in the veins, especially in the legs (see page 605). Beta blockers (see page 562) may be given to help reduce the heart’s workload by slowing the heartbeat and lowering blood pressure.
You may be given thrombolytic (clot-dissolving) drugs (see page 563) to dissolve the blood clot that is blocking the coronary artery. However, this treatment is effective only if no more than 6 hours have passed since the onset of symptoms. In most cases, thrombolytic drugs are given (usually by injection directly into a vein) as soon as the diagnosis of a heart attack is confirmed.
Surgery
You will have additional tests, such as a coronary angiogram (see page 561), to determine whether the clot has dissolved and blood flow has been restored. If the tests show that the coronary artery is still blocked, a procedure such as angioplasty (see page 565) may be performed to reopen the artery. If the artery becomes blocked again after surgery, the procedure may be repeated a few days later.
As an alternative to treatment with a thrombolytic drug, your doctor may perform immediate angioplasty of the blocked blood vessel using specially designed instruments to remove the blood clot from the artery. Balloons and stents may be used to open the artery. In many cases, immediate angioplasty for a heart attack can be as effective as treatment with thrombolytic drugs in limiting the damage caused by a heart attack and improving a person’s chances of survival. In rare cases a doctor may perform emergency coronary artery bypass surgery (see page 564) at the time of a heart attack.
Preventing Another Heart Attack
If you have had a heart