Overview of Myocardial Infarction
Myocardial infarction (MI) or heart attack is a medical emergency condition in which the blood supply to the heart suddenly reduces or stops, causing the myocardium to die from lack of oxygen (myocardial ischemia). Myocardial infarction is the most dominant manifestationof ischemic heart diseases (IHDs).1 Although it may be a minor event in a lifelong chronic disease and remains undetected, MI frequently leads to sudden death in both men and women all over the world.
Approximately one-third of individuals die of cardiovascular diseases (CVDs) globally and 80% of these deaths occur in developing countries.2 In India, the deaths due to CVDs are expected to increase from 1.17 million in 1990 and 1.59 million in 2000 to 2.03 million by the year 2010.3
A definite diagnosis of MI can be made in patients who have a number of atherosclerotic risk factors along with the presence of symptoms consistent with myocardial ischemia. The goals of the therapy in MI are immediate restoration of normal coronary blood flow and maximum salvage of functional myocardium. These therapeutic goals can be achieved through appropriate and timely medical interventions.
Pathophysiology (How Myocardial Infarction Developes)
The commonest cause of MI is rupture of an atherosclerotic plaque within a coronary artery followed by arterial spasm and subsequent thrombus formation. The severity of an MI depends on the level and duration of the arterial occlusion. More the proximal coronary occlusion, the greater is the chance of death due to a mechanical complication. When the duration of the occlusion is prolonged, there are more chances of irreversible myocardial damage distal to the occlusion.
Risk Factors for Myocardial Infarction
Read more details about the risk factors for myocardial infarction
Clinical Features (Symptoms of myocardial infarction)
The most common symptom of acute MI is chest pain, which is similar to angina but usually more severe, persists for longer duration and not relieved by taking rest or consuming sublingual nitrates. The pain is described as a sensation Read more details....
Diagnosis of Myocardial Infarction
The definite diagnosis of acute MI is based on the WHO criteria, which requires either defined electrocardiography (ECG) changes or ischemic symptoms and presence of cardiac biomarkers (preferably troponin).4 Several
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Treatment of Myocardial Infarction
Emergency First-Line Therapy
Reperfusion
Read more details about the treatment of myocardial infarction
Complications of Myocardial Infarction
Some possible complications that may occur after an MI include the following:
- Myocardial rupture.
- Pericarditis.
- Congestive heart failure—A condition that impairs the ability of the heart to pump sufficient blood through the body.
- Arrhythmias—Abnormal heart rhythms.
- Cardiogenic shock—A state of inadequate tissue perfusion due to cardiac dysfunction.
Cardiac rehabilitation is the process by which a MI patient or a patient with IHD is encouraged to achieve their full potential in terms of physical and psychological health. Cardiac rehabilitation includes a program of structured exercise, which improves morbidity and reduces mortality in MI patients. Other rehabilitation programs are general health education and information on stress management.
Risk-factor modification is an important aspect in the reduction and alleviation of myocardial ischemia. Indeed, use of medical therapy in controlling the risk factor may reduce the risk of future cardiac events to a greater degree than revascularization strategies.
Secondary prevention of CVDs includes general measures and specific drug therapy, according to the individual risk pattern. Among the general measures, cessation of smoking is most important, followed by daily exercise (avoid exerting activities), maintenance of optimal body weight and a healthy diet. In most cases, secondary prevention also includes specific drug therapies. Aspirin, statins, beta-blockers and ACE (angiotensin-converting enzyme) inhibitors are the cornerstones of this drug therapy.
Written by: Healthplus24 team
Date last updated: December 19,2008