Myocardial Infarction Cause Symptom Treatment
Myocardial Infarction
Myocardial infarction is defined as localized necrosis of cells due to lack of blood supply to the heart muscles (Ischemia - lack of blood supply to heart muscles).
It results from long term deprivation of blood supply that causes myocardial tissues deprived of oxygen resulting in damage and cell death (necrosis).
It result in further damage to complete heart muscle characterized by decreased muscle contraction, decreased oxygen supply and cardiac output diminish.
CAUSES
Myocardial infarction primarily occurs due to less blood supply to heart layer for prolonged time causing death of tissues and cells via inadequate oxygen and tissue perfusion.
Causes of myocardial infarction
- Narrowing of artery
The narrow artery supply less blood to tissues. It decrease size of blood vessels so thus it causes ischemia. Prolonged narrowing of artery can result in necrosis of cells.
- Atherosclerosis
Atherosclerosis is define as plaque formation inside blood vessels which decrease space for blood flow. During atherosclerosis, ischemia occurs resulting in decreased tissue perfusion and tissue hypoxia.
- Decreased blood supply due to block artery
Heart muscles didn't receive blood due to presence of blockage in blood vessels. Ex. blood clot, tissue accumulation could block flow of blood to heat causing ischemia.
- Over constriction of blood vessels
Constriction of blood vessels causes less blood supply to body cells. It is occur in hormonal imbalance, and in infection conditions. It could diminish blood supply to body cells for a prolonged time.
- Reduced heart contractibility
Decrease myocardial contractibility result in decreasing the pumping action of heart and low cardiac output. It causes low blood volume to pump or blood is pump less forcefully to reach cardiac cells.
- Pulmonary embolism
Pulmonary embolism is defined as blockage of the pulmonary artery due to some material is entered in blood vessels. It can blood clot and foreign particle.
Risk factors
- Family history
- Blood clot
- Obesity
- Prolonged stress
- Low physically active person
- Heart surgery
- Diabetic mellitus
- Hyperlipidemia
- Hypoglycemia
- Smoking
- Substance abuse
- Trauma to heart
Myocardial Infarction Symptoms
Myocardial infarction leads to develop following symptoms:-
- Chest pain
Chest pain arises in sternum area it also occur in arm, shoulder, neck and back. It is not recover by simple rest. It sustain for half an hour.
- Decreased heart contractility
Ischemia decreases tissue perfusion and cell undergoes to hypoxia. It decreases the hearts contractile ability resulting in less contraction of heart.
- Low cardiac output
It occur when heart fails to pump enough blood to body due to decreased muscle contractility.
- Tachycardia
It occurs due to sympathetic stimulation causing vasoconstriction to improve blood flow to heart.
- Palpitation
- Moist skin
During myocardial infarction, there will be decreased blood to all body parts. It can cause dry skin due to less tissue perfusion.
- Extreme fatigue
It arises due to low oxygen level in the body. Patient may get tired up early and feel weakened.
Other symptoms are,
- Abdominal pain
- Decreased urine output
- Anxiousness
- Disorientation, fainting
- Increased respiratory rate
Pathophysiology
Myocardial infarction begins with specific causes such as blood clot, vasoconstriction, narrowing of artery etc. It results in ischemia (low blood volume reaches to the heart cells).
It then results in hypoxia (oxygen deprivation) and decreasing myocardial contractibility. Low blood oxygen level injure normal cells resulting in decreasing function. It leads to the loosening of muscle elasticity and decreasing cardiac output.
Arterial blood pressure decreases stimulating baroreceptor which in turn causes vasoconstriction to increased blood flow and oxygen supply.
It then results in hypoxia (oxygen deprivation) and decreasing myocardial contractibility. Low blood oxygen level injure normal cells resulting in decreasing function. It leads to the loosening of muscle elasticity and decreasing cardiac output.
Arterial blood pressure decreases stimulating baroreceptor which in turn causes vasoconstriction to increased blood flow and oxygen supply.
The continuous lessening blood supply result in the insufficiency of tissue perfusion (hypoxia) causing ischemia. It lead to cell death, necrosis causing myocardial infarction.
Diagnosis
Myocardial infarction is diagnosed by following test:-
- Sign and symptoms of patient
- Electrocardiogram
- Angiography
- Complete blood count test (CBC)
- For increased white blood cell count
- Chest x-ray
Treatment of Myocardial Infarction
Myocardial infarction is managed by medicine and surgical procedures. Aim of treatment is to increased blood flow to heart, increase heart function and minimizes damages and prevent complications.
Medical therapy includes,
- Analgesic drug
It is given to decrease pain such as dyspnea (chest pain), pain arise in head, back, shoulder etc. Ex. Morphine is given as analgesic drug.
- Vasodilator drug
Vasodilator mean drug that dilates and widen blood vessels to increased blood flow. ex. Nitroglycerine is given to as vasodilator to improve blood flow to heart muscles.
- Beta blocker
Beta blocker blocks sympathetic nervous system resulting in decreasing load over heart. It enhances oxygen supply to cells and promotes blood flow in blood vessels.
- Oxygen therapy
It is given when patient suffer from low oxygen level or have severe chest pain or feeling breathlessness etc. It increases and maintains oxygen level in body.
- Thrombolytic therapy
Thrombolytic therapy involves drugs that break thrombus (blood clot) present in blood vessels.
- Angiotensin-converting enzyme
It is given in chest pain and to decrease heart load. It maintains body fluid level by retaining fluid from the kidney. Angiotensin I Constrict blood vessels and retain sodium and chloride and water. Angiotensin II promotes vasodilation and promotes diuresis to decreases fluid volume and afterload over the heart.
- Calcium channel blocker
It enhances oxygen supply decreased load on hear and maintain normal blood flow.
Surgical Management
- Coronary artery bypass surgery
Coronary artery bypass surgery (CABS) is invasive procedure performed in complete blockage of coronary artery. It involve passing blood flow to heart cells by connecting other blood vessels from blocked area so that blood should go to heart.
- Angioplasty
Angioplasty is an invasive procedure help in widening and opening of blood vessels. A tube attached with ballon is insert in blood vessels at blockage which then widen blocked area. It fixes and eliminate the plaque form inside the blood vessels. It is also called as ballon angioplaty, percutaneous transluminal angioplasty.
- Coronary stent
A stent is small circular metal sheath structure placed in blocked arteries. It keep artery open it is performed in patient with repeat plaque formation and to treat chronic coronary artery diseases.
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