This document defines myocardial infarction (also known as a heart attack) as damage to the heart muscle caused by reduced blood supply. It occurs when a coronary artery becomes blocked, and discusses the causes, locations in the heart, types, pathophysiology, signs and symptoms, diagnostic tests, treatments including medications and procedures, and nursing management goals related to pain, tissue perfusion, anxiety, and activity intolerance.
3. DEFINITION :
• It occurs when blood supply decreases or stops in one of the coronary
arteries of the heart causing damage to the heart.
• It is a clinical syndrome that results from occlusion of coronary artery
with resultant death of cardiac myocytes.
• It is the permanent damage of myocardium tissue caused by reduced
coronary blood supply to the myocardial tissue.
• It is also called as “Heart Attack”.
6. SITE OF MYOCARDIAL INFARCTION :
1) Left ventricle (commonest)
- Anterior wall of the left ventricle + apex
- Lateral wall of the left ventricle
- Posterior wall of the left ventricle
2) Right ventricle (rare)
- Due to the occlusion of the right coronary artery.
7. CLASSIFICATION / TYPES :
1) STEMI : an ST Segment Elevation Myocardial Infarction it is a type
of heart attack that mainly affects Heart’s lower chambers and changes
electrical current travels through them. It is tend to be more severe and
dangerous.
2) NSTEMI : Non ST Segment Elevation Myocardial Infarction it is a
type involving partial blockage of one of the coronary arteries causing
reduced flow of blood to heart muscle. It is less serious compared to
STEMI.
8. PATHOPHYSIOLOGY :
Due to etiological factors (coronary artery embolism)
Reduced Myocardial blood supply
Increase myocardial oxygen demand
Myocardial Ischemia
Necrosis of affected tissue
Myocardial Infarction
10. DIAGNOSTIC STUDIES :
- History collection
- Physical examination
- ECG (ST Segment Elevation)
- Blood test : to check cardiac markers like Troponin & CK-MB, CRP,
Myoglobin)
- Coronary Angiography
- CT Scan
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12. MANAGEMENT :
MEDICAL :
Follow MONATAS.
Morphine : Analgesics to reduce chest pain.
Oxygen : To improve oxygenation.
Nitroglycerin : It causes vasodilation and increase blood supply to
myocardium. (intravenous)
Aspirin : Anti - platelet, which prevents formation of clot / thrombus.
Thrombolytics : To break and dissolve thrombus.
Anticoagulant (LMWH): To prevent the formation of clot.
Sedatives : To give rest to patient
13. DRUGS MECHANISM
Beta Adrenergic Blockers :
propranolol
Inhibit sympathetic nervous stimulation of
heart
Glycoprotein IIB / IIIA inhibitors :
Tirofiban
Prevent binding of fibrinogen to platelets,
thereby blocks platelet aggregation.
Direct thrombin inhibitors :
Lepirudin
Prevent binding of thrombin & subsequent
clot formation.
Fibrinolytic therapy :
streptokinase
Breaks up fibrin meshwork in clots & used
only in STEMI.
Calcium Channel Blockers :
Nifedipine, Nicardipine
Coronary artery & peripheral vasodilators.
Angiotensin – Converting Enzyme
inhibitors : Enalapril
Prevents conversion of Angiotensin I to
Angiotensin II
14. SURGICAL :
1. Coronary Artery Bypass Graft (CABG) : it is the 1st option when
more than two arteries are blocked.
2. Percutaneous Transluminal Coronary Angioplasty (PTCA) : It is
minimally invasive procedure to open blocked arteries allowing
unobstructed blood flow to myocardium.
3. Coronary Stent : it is a tube shaped instrument placed in the coronary
artery.
4. Atherectomy : it is a procedure that utilizes catheter with sharp blade
on the end to remove plaque from blood vessel.
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20. NURSING MANAGEMENT :
1. Pain, Acute, Chest related to decreased myocardial blood supply.
Interventions :
- monitor the severity of pain by using rating scale (0 to 10) & evaluate
the pain for intensity, location, radiation, duration and precipitating
factors.
- Provide comfortable position (Semi fowlers)
- Advice complete bed rest.
- Monitor the vital signs frequently.
- Administer medications as per the advice (Nitroglycerin, Morphine
sulphate)
21. 2. Ineffective tissue perfusion related to myocardial injury and pulmonary
congestion.
Interventions :
• Monitor oxygen saturation every hour to get baseline data.
• Provide oxygen through nasal cannula.
• Ensure the patient rest to reduce oxygen demand.
• Make sure about the positioning of patient (Fowlers / Semi fowlers)
• Educate the patient about breathing & Coughing exercises.
• Administer the medications (vasodilators, Beta blockers)
22. 3. Anxiety related to perceived or actual threat to death, pain and
possible lifestyle changes.
Interventions :
• Monitor patient for verbal & non verbal signs of anxiety.
• Use a calm and reassuring approach while talking to patients.
• Encourage the family members to stay with patient.
• Instruct patient on the use of relaxation techniques (guided imagery)
• Motivate the patient to ventilate his feelings.
• Clear all the doubts of patient by using simple local language.
23. 4. Activity intolerance related to fatigue, decreased cardiac output and
poor tissue perfusion.
Interventions :
• Monitor the patient’s response to activity & antiarrhythmic
medications.
• Explain the patient about energy conservation principles.
• Arrange the exercise and bed rest alternatively.
• Encourage patient to do self care activities that minimize oxygen
consumption.
• Provide calm environment & limit visitors.
• Assist patient in self care activities if needed.
