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Myocardial Infarction [MI] (Risk factors (Age (Men over 45 year and women…
Myocardial Infarction [MI]
Occurs because blood flow is decreased or stopped to a section of the heart, resulting in irreversible cell death.
How is happens
A MI occurs when an atherosclerotic plaque builds up within the inner lining of the coronary artery and then suddenly ruptures, causing a thrombus formation which prevents blood flow to the myocardium distal to the blockage, resulting in necrosis to that specific area of the heart.
The process of a MI takes time. Cardiac cells within the heart can with stand ischaemic conditions for approximately 20 minutes before cell death begins to occur. If these ischaemic conditions occur, it takes around 4-6 hours for the entire thickness of the heart muscle to become necrosed.
Signs and symptoms
Pain/pressure and tightness in the chest
Cardiovascular symptoms
Elevated blood pressure and heart rate
Decreased renal and urine output
Crackles heard upon auscultation
Abnormal heart sounds
Peripheral oedema
Fever, accompanied with sweating
Nausea and vomiting
Shortness of breath
Pain in the chest, back, jaw and other areas of the upper body
Risk factors
Family history
Age
Men over 45 year and women over 55 years
Smoking, as well as exposure to second hand smoke
High blood pressure
High blood cholesterol levels
Physical inactivity
Obesity
Stress
Diagnosis
To diagnose a MI this involved medical staff discussing your symptoms and measuring your blood pressure, pulse and temperature. Questions surrounding risk factors and family history may also be asked. Tests that can help with the diagnosis include:
Electrocardiogram [ECG]
This monitors the electrical activity of the heart. This will look for changes in the QRS complex, ST segment and T wave that is caused by a MI
Blood tests
To test for the presence of specific proteins that leak into the blood if the heart muscle has been damaged. This group of proteins are known as troponins
Chest x-ray
To measure the size of the heart and the coronary arteries
Echocardiogram
This is done via an ultrasound machine that uses sound waves to produce moving images of the heart to reveal any abnormalities cause by damage to the heart
Cardiac computerised tomography [CT] or magnetic resonance imaging [MRI]
Reveals problems with the hears and coronary arteries by providing a number of detailed images
Coronary angiogram
This is a imagining technique that shows the extent of the MI and which arteries are narrowed/blocked
Treatment
Treatment can vary depending on the severity of the heart attack and the amount of damage that has occurred. The main aim of treatment tis to restore the flow of blood to the heart. Treatment may include:
Thrombolytics
These drugs work to activate the natural anti clotting system. The activation of this system breaks down fibrin threads and dissolves any formed clots
Aspirin
This drug inhibits platelet adhesion and aggression by blocking receptor sites on the platelet membrane, preventing the formation of blood clots
Nitroglycerin (GTN)
This drug works by relaxing and dilating the veins, arteries and capillaries, allowing for an increased blood flow through the vessels and lowering systemic blood pressure
Beta blockers
These drugs work by binding to beta-adrenoceptors. These drugs allow for a decrease in heart rate, contractility and excitability. Resulting in a decrease in arrhythmias, decreased cardiac workload and decreased oxygen consumption
ACE inhibitors
These work in the lungs and prevent ACE from converting angiotensin I to angiotensin II. This results in a decrease in blood pressure.
Cholesterol lower drugs (statins)
These drugs work by blocking HMG-CoA from completing synthesis of cholesterol, lowering these unwanted levels from the blood
Prevention
Quit smoking
Control high blood pressure and cholesterol levels
Exercise regularly
Maintain a healthy diet
Reduce stress
Avoid drinking alcohol, or do so in moderation
Maintain a healthy weight