The heart is a muscular organ that pumps blood through a system of veins (veins) and arteries (arteries). Blood flows into the heart from the lungs, where it receives oxygen through the pulmonary veins; The heart pumps blood throughout the body, delivering oxygen to the tissues. The blood returns to the heart and is once again pumped to the lungs. To fulfill these tasks, the heart needs plenty of oxygen from the blood.
Acute myocardial infarction (AMI), also called a heart attack, occurs as a result of blockage of the heart arteries that reduce or completely cut off the blood supply to a certain part of the heart. A blood clot usually causes a blockage in an area that restricts blood flow due to a thickening of the inside of an artery wall. Plaque formation , also called atherosclerosis , causes thickening of the vessel wall. Sudden ( acute ) blockage of blood flow for more than one hour by a clot (if present) can lead to death of heart muscle cells (infarction), scarring of the diseased part of the heart (wound).
The term acute coronary syndrome (ACS) refers to signs and symptoms that result from insufficient blood flow to the heart . Symptoms may include chest pain that comes on suddenly, often radiating to the jaw, arm, or shoulder. These complaints may be more severe or prolonged than normal in patients with angina . Some of the patients may show symptoms such as rapid pulse, nausea, vomiting, sweating, sudden onset shortness of breath, and difficulty in breathing. In some cases (especially in the elderly and diabetesThese symptoms occur without chest pain. These symptoms may also be accompanied by changes in blood pressure. Symptoms in women are less dramatic and are more likely to be misinterpreted by another cause than men. For more information on warning signs and differences between men and women , see the links under Related pages, Another website . Call 112 if you show these signs of illness. If you do not seek immediate medical attention, irreversible damage to the heart muscle may occur.
When a patient presents with symptoms of acute coronary syndrome, it is often unclear whether these symptoms indicate acute myocardial infarction or merely a temporary occlusion. Many tests are available to help evaluate whether an acute myocardial infarction has occurred.
Heart attack diagnosis on an electrocardiogram (ECG)It can be diagnosed by changes seen and a series of blood tests. An ECG is taken within the first few minutes after the patient with acute coronary syndrome arrives at the emergency department. The EKG can detect changes that suggest a severe heart attack has occurred. However, this diagnostic change is only seen in the most severe AMI. More often, the ECG confirms the presence of nonspecific changes that do not prove that the heart is not getting enough blood or that AMI has occurred. Patients with the most severe ECG changes (ST elevation, meaning elevation of the line joining the S and T segments on the ECG trace) usually have a large clot in the arteries supplying the heart and should be treated quickly with either medications or cardiac catheterization to remove the clot.
The remainder of patients with acute coronary syndrome will need blood tests to determine whether AMI has occurred. Blood tests are a measure of heart muscle damage. When a part of the muscle loses its vitality, dead cells release chemicals into the blood. These chemicals include CK-MB , myoglobin , and troponin . Measuring the levels of heart biomarkers can detect a heart attack and roughly indicate the extent of muscle breakdown. These tests are also used in the diagnosis, evaluation and follow-up of patients with suspected acute coronary syndrome.
In order to diagnose a heart attack, tests other than laboratory tests such as nuclear scanning and coronary angiography can also be applied.
As with all heart diseases , controlling high blood pressure ( hypertension ) is the main cause of concern. Depending on the reaction of the heart, digoxin, which helps to strengthen the heart contractions, and procainamide-like rhythm regulators that help synchronize the contractions can also be used. Beta blockers , ACE inhibitors, anticoagulants , antiplatelet drugs, thrombolytic drugs that dissolve or break up blood clots may also be prescribed. Sometimes, medical interventions such as angioplasty or coronary artery bypass grafting are needed. Your doctor can recommend appropriate diet and exercise changes for your condition.
Sources of the article
Resources Used in This Review
National Heart, Lung, and Blood Institute. National Heart Attack Alert Program: Testing for a Heart Attack. http://rover.nhlbi.nih.gov/actintime/taha/taha.htm http://rover.nhlbi.nih.gov. İnternete girişi: Eylül 2008.
National Heart, Lung, and Blood Institute. National Heart Attack Alert Program: How is a Heart Attack Treated? http://www.nhlbi.nih.gov/health/dci/Diseases/HeartAttack/HeartAttack_Treatments.html http://rover.nhlbi.nih.gov. İnternete girişi: Eylül 2008.
American Heart Association: What is Acute Coronary Syndrome? http://www.americanheart.org/presenter.jhtml?identifier=3010002 . Internet access: July 2008.
Achar, SA et al. Diagnosis of Acute Coronary Syndrome. American Family Physician. July 1, 2005. http://www.aafp.org/afp/20050701/119.html http://www.aafp.org . Internet access October 2008.
Sources used in previous reviews
Thomas, Clayton L., Editor (1997). Taber’s Cyclopedic Medical Dictionary. FA Davis Company, Philadelphia, PA [18th Edition].
http://dx.doi.org/10.1037/0033-295X.100.1.101 Pagana, Kathleen D. & Pagana, Timothy J. (2001). Mosby’s Diagnostic and Laboratory Test Reference 5th Edition: Mosby, Inc., St. Louis, MO.