Acute Myocardial Infarction
The location and extent of infarction depend upon the anatomic distribution of the occluded vessel, the presence of additional stenotic lesions, and the adequacy of collateral circulation. Thrombosis in the anterior descending branch of the left coronary artery results in infarction of the anterior left ventricle and interventricular septum. Occlusion of the left circumflex artery produces anterolateral or posterolateral infarction. Right coronary thrombosis leads to infarction of the posteroinferior portion of the left ventricle and generally involves the right ventricular myocardium if the obstruction is proximal. The arteries supplying the atrioventricular node and the sinus node more commonly arise from the right coronary; thus, atrioventricular block at the nodal level and sinus node dysfunction occur more frequently during inferior or right-sided infarctions. Individual variation in coronary anatomy and the presence of collateral vessels can make the prediction of coronary anatomy from infarct location imperfect.
Acute Myocardial Infarction occurs when myocardial ischemia exceeds a critical threshold and overwhelms myocardial cellular repair mechanisms that are designed to maintain normal operating function and hemostasis. Acute Myocardial Infarction commonly known as a heart attack. Acute Myocardial Infarction is a disease that occurs when the blood supply to a part of the heart is interrupted, causing death of heart tissue. The term myocardial infarction is derived from myocardium (the heart muscle) and infarction (tissue death due to oxygen starvation or ischemia ). The phrase "heart attack" sometimes refers to heart problems other than MI, such as unstable angina pectoris and sudden cardiac death .
Myocardial infarction can be subcategorized on the basis of anatomic, morphologic, and diagnostic clinical information. From an anatomic or morphologic standpoint, the two types of Acute Myocardial Infarction are transmural and nontransmural. Critical myocardial ischemia may occur as a result of increased myocardial metabolic demand and/or decreased delivery of oxygen and nutrients to the myocardium via the coronary circulation. A heart attack (myocardial infarction) occurs when an area of heart muscle dies or is permanently damaged because of an inadequate supply of oxygen to that area.
Cause of Acute Myocardial Infarction
Some are common causes of Acute Myocardial Infarction:
Symptoms of Acute Myocardial Infarction
Premonitory pain - Many patients give a history of alteration in the pattern of angina preceding the time of onset of symptoms of myocardial infarction, classically the onset of angina with minimal exertion or at rest.
Pain of infarction - Unlike anginal episodes, most infarctions occur at rest, and more commonly in the early morning. The pain is similar to angina in location and radiation but it may be more severe, and it builds up rapidly or in waves to maximum intensity over a few minutes or longer. Nitroglycerin has little effect; even opioids may not relieve the pain.
Associated symptoms of Acute Myocardial Infarction
Patients may break out in a cold sweat, feel weak and apprehensive, and move about, seeking a position of comfort. They prefer not to lie quietly. Light-headedness, syncope, dyspnea, orthopnea, cough, wheezing, nausea and vomiting, or abdominal bloating may be present singly or in any combination. Some are common symptoms of Acute Myocardial Infarction:
Treatment of Acute Myocardial Infarction
All patients with definite or suspected myocardial infarction should receive aspirin at a dose of 162 mg or 325 mg at once regardless of whether thrombolytic therapy is being considered or the patient has been taking aspirin. Chewable aspirin provides more rapid blood levels. Patients with a definite aspirin allergy may be treated with clopidogrel 300 mg, though the onset of its effectiveness will be slower. The most common treatment of Acute Myocardial Infarction:
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