Myocardialinfarction, also known as heart attack, is a major health problem inall societies. The condition occurs when the coronary artery iscompletely and suddenly blocked causing the damage of the cardiacmuscles as a result of insufficient supply of oxygen and food (Thow,Graham & Lee, C. 2013). The heart muscles are supplied withoxygen and food materials by two large coronary arteries. Blockage ofone coronary artery results in inadequate or lack of oxygen supplyand heart becomes starved, leading to a condition referred to asischemia. The condition may take a short period to be reversed.However, when it is prolonged, irreversible death of the cardiactissues occurs. The death of heart tissues is referred to asmyocardial infarction. This paper focuses on the etiology,pathophysiology, symptoms and diagnosis of heart attack.
The common cause of blockage of the coronary artery is blood clot,thrombosis. Three mechanisms can result in blockage of the coronaryartery: plaque rupture, new coronary artery thrombosis, vasospasmclose to the rapture of plaque. Some conditions elevate the risk ofdeveloping a heart attack. Hypertension can result in the obstructionof the coronary artery, and formation of plaque that causes theblockage. High level of cholesterol in the blood risks an individualof developing a heart attack. The low-density lipopolysaccharidecholesterol may stick on the walls of the coronary artery, leading toits blockage. Other risk factors for the disease include diabetes,obesity, aging, stress, heredity, and lack of physical exercise(Clifford et al., 2012).
Thepathophysiology of myocardial infarction can be described in threestages ischemia, injury, and infarction. Thrombus builds up to blockthe artery, and spasm may occur along with partial occlusion by anatheroma resulting in complete blockage (Thow, Graham & Lee, C.2013). Part of the thrombus may break and form emboli, and then flowsthrough the coronary artery until smaller branches where they blackthat vessel. Therefore, the blood supply to the cardiac tissues iscut resulting in ischemia. The zone of ischemia is composed of viablecells whose repolarization is temporarily impaired. The injury stageis characterized by incomplete repolarization due to deficient supplyof blood. The injury can either be coagulation necrosis that resultsfrom persistent obstruction of blood flow or contraction bandnecrosis that results when coronary reflow follows a period of noperfusion (VanMeter, Hubert & Gould, 2014). The injury causes theirreversible death of the cardiac cells, infarction. All the layersof the cardiac and the left ventricle are usually affected. Thefunctions of myocardial contractility and conduction are lostsuddenly and eventually leading to heart attack.
Damage of hearttissues is accompanied by tightness, pain or squeezing sensation inthe chest. These symptoms may spread to other parts especially theneck, jaw, arms, legs or back. An individual suffering from heartattack experiences sudden dizziness, shortness of breath and fatiguethat may result in fainting. The symptoms usually last for over 15minutes but sometimes even for several hours. If not detected andmanaged at early stages, a large portion of the heart tissues isdamage (Thygesen et al., 2012). This results in complicationsthat may lead to sudden collapsing or even death of an individual.Other symptoms include nausea, indigestion, heartburn and abdominalpain. The symptoms vary with patients where some exhibit severalsymptoms while others experience a few of the symptoms.
The most commondiagnostic techniques of myocardial infarction include blood test ofcardiac enzymes, and electrocardiogram (ECG). Electrocardiogram isbased on the electric conductivity of the heart. Since damage heartmuscles do not have normal electric conductivity, ECG shows whetheran individual is suffering or suffered from a heart attack (Cliffordet al., 2012). Imaging tests such as chest X-ray, angiogram,and MRI can be used in the diagnosis. The imaging techniques takeimages of the heart which are used in the identification ofabnormalities of the heart muscles.
Myocardialinfarction is caused by the irreversible death of the cardiactissues. The death of the cells of the heart is caused byinsufficient supply of food and oxygen by blood through the coronaryarteries. The supply of blood to the cardiac tissues is cut when thecoronary artery is blocked. Thrombosis is the primary cause ofcoronary artery blockage. Conditions such as high level ofcholesterol in the blood, diabetes, obesity, aging, stress, heredity,and lack of physical exercise increase the risk of suffering frommyocardial infarction. Heart attack progresses in in three stagesischemia, injury, and infarction. The symptoms of this condition maybe different in various patients. Electrocardiogram is the commondiagnostic technique, but imaging tests and blood test of cardiacenzymes can also be used.
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