Acute Myocardial Infarction: Emergency Management and Hospital Treatment Guide

Acute Myocardial Infarction: Emergency Management and Hospital Treatment Guide

Question. Describe briefly the management of acute myocardial infarction.
Or
Outline the management of acute myocardial infarction.

Answer. The management of myocardial infarction is divided into two parts:
1. Early management.
2. Late management.

Early Management of acute myocardial infarction:

1. Aspirin 150–300 mg to be chewed earliest.
2. Sublingual glyceryl trinitrate 0.4–1 mg, to be repeated, if necessary
3. Oxygen through nasal cannula at a rate of 2–4 L/min.
4. Procure IV line and take blood samples for glucose, lipids and complete haemogram.
5. Record 12­lead ECG.
6. Pain may be relieved by IV morphine (5 mg) plus metoclopramide as an antimetic (10 mg).
7. IV beta­blockers (metoprolol 5 mg every 2–5 minutes for 3 doses) for ongoing chest pain, hypertension and tachycardia provided there is no contraindication.
8. Thrombolysis should be done.
9. If PTCA is planned, give GP IIb/IIIa inhibitor
10. After admission immediately shift the patient to ICU or
    ICCU

Acute Myocardial Infarction: Emergency Management and Hospital Treatment

In Hospital treatment acute myocardial infarction.

Hospitalization and strict Bed rest:

Hospitalize the patient and advice strict bed rest. As early as the patient is hospitalized, the bettr it is.

1. Patient should be strictly admittd in ICCU.

Analgesia acute myocardial infarction.

1. IV morphine sulphate 10 mg and an anti emetic, i.e. cyclizine 50 mg is given through I.V. cannula.
2. The drug is repeated depending on the response till complete analgesia is received and patient feels bettr.

Anti-platelet drugs acute myocardial infarction.

Low dose aspirin, i.e. 75 to 150 mg and clopidogrel 300 mg stat and then 75 mg orally daily is given.

Oxygen therapy acute myocardial infarction.

Inhalation of oxygen increases arterial partial pressure of oxygen, so there is increase in the concentration of oxygen gradient which is responsible for diffusionn of oxygen in ischemic myocardium from adjacent better perfused areas. This is given by facemask or nasal prongs for a day or two after infarction.

Emergency Management of Acute Myocardial Infarction

Thrombolysis acute myocardial infarction.

1. Coronary thrombolysis helps to restore patency of coronary artery preserves left ventricular function and improves survival.
2. The choice of drug for thrombolysis is less important than the speed of treatment.
3. Streptokinase, 1.5 million units in 100 mL of saline given in an intravenous infusion over 1 hour, is a widely accepted method.
   It is a cheap, but being antigenic, sometimes, may cause serious allergic manifestations.
   Hence, it can be used once and therapy is changed if the patient requires second thrombolysis within few years.

Alteplase (tissue Plasminagen activator (tPa)

1. It is a potent firinolytic drug but is expensive.
2. It is less antigenic and does not cause hypotension.
3. The current tPA regimen given over 90 minutes (bolus dose of 15 mg followed by 50 mg over 30 minutes and then 35 mg over next 60 minutes) is widely accepted. The other drugs include reteplase given in double dose regime i.e.
   10 million units over 2–3 minute followed by another dose of 10 million units after 30 minutes.
   Tenectaplase given as bolus dose of 53 mg/kg over 10 seconds. Both reteplase and tenectaplase are known as bolus firinolytics.

Angioplasty
Immediate angioplasty of infarct related artery is safe and is effctive alternative to thrombolysis. It is done in the patients in whom the hazards of thrombolysis is high.

Anti-coagulants

1. Sub­cutaneous heparin, i.e. 7,500 units twice a day for 7–10 days or till discharge of patient from the hospital can be employed.
   In patients who do not receive thrombolytic therapy to prevent venous thrombosis.
2. Patients who receive thrombolytic therapy (tPA) should receive immediate and full doses of heparin (10,000 U bolus plus, l000 U hourly).

Beta-adrenergic Blockers

Acute beta­adrenoreceptors blockade intravenous atenolol (5–l0 mg given over 5 minutes) or metoprolol (5–15 mg given over 5 minutes) relieves pain, reduces arrhythmias, salvages myocardium and improves short term mortality in patients who present within l2 hours of onset of pain.

Nitrates and other agents

Sublingual glyceryl trinitrate 0.4 mg is useful in threatened infarction.

Sedatives

Diazepam 5mg for three to four times a day is effctive. It is given for few days.

Diet

1. For fist 4 to 5 days low calorie diet which is divided into multiple meals is given.
2. If heart failure is present restrict the salt.
3. From second week, food should be increased in amount.

Lipid lowering agent
Atorvastatin is given to reduce the LDL levels.

Late Management acute myocardial infarction.

1. Risk stratifiation and further investigations: Prognosis of patient survived after myocardial infarction depends on degree of myocardial damage, any residual ischemia and presence of ventricular arrhythmias.

2. Life style modifiation:

1. Stop smoking
2. Diet control
3. Regular exercise.

3. Secondary prevention

1. Antiplatelet agents, i.e. aspirin
2. Lipid lowering agents
3. Beta­blockers and ACEI in congestive cardiac failure and hypertension.
4. Control of blood sugar in diabetes.

4. Rehabilitation and after care:

1. Physical activities should be restricted for 4 to 6 weeks since infarct takes 4–6 weeks to become replaced with firous tissue.
2. Gradual mobilization and return to work over 6 weeks.
   When there are complications, the regimen has to be modifid accordingly.
3. Exercise within the limits set by angina and tiredness will do no harm but much good. Same limits apply to sexual activity.
4. Control of obesity, regular exercises, cessation of smoking, adoption of a less frenetic way of life and control of plasma lipids by diets and drugs.
5. Complications should be managed. Pain relief, reassurance, rest and correction of hypokalemia play a major role in prevention of arrhythmias.

Routine drug therapy acute myocardial infarction.

1. Low dose aspirin, i.e. 75 to 150 mg daily and is continued indefiitely.
2. Beta-adrenergic blocker should be given for 4 to 6 weeks if there is no contraindication.
3. ACE inhibitor, i.e. captopril 25 mg TID or ramipril 2.5 to 5 mg BD
4. Lipid lowering agent atorvastatin is given to lower the LDL levels.