Management Of Patients With Acute Myocardial Infarction And Its Complications
Patients With Myocardial Infarction Should Be Hospitalized
ECG Denoting Myocardial Infarction
Management of acute myocardial infarction is one of the most frequent and exacting emergencies occurring in the medical wards. All patients with suspected myocardial infarction should be hospitalize and put to rest. It is ideal to monitor the heart rate, blood pressure, respiration and the electrocardiogram in an intensive coronary care unit (ICCU) whenever available. This unit is equipped with all machines for monitoring and provision for handling emergencies such as cardiac arrest, ventricular fibrillation, heart block, acute pulmonary edema and shock. All the treatable and preventable emergencies which demand immediate attention can be promptly attended to, so that many lives can be saved, which would be lost if treated in general wards. In uncomplicated cases, the period for ICCU monitoring is 48-72 hours.
Relief of pain: Morphine is administered 5-10mg by slow intravenous injection, repeated every 15 min till the pain is relieved. Morphine relieves pain, reduces anxiety and causes dilatation of peripheral arteries and veins. Morphine may cause bradycardia. This can be avoided by the prior or concurrent administration of 0.4mg atropine. Alternatives to morphine are Pethidine 50-100 mg and pentazosin. A venous line is established by starting a drip of 5% glucose.
Rest: Absolute bed rest is instituted for the first 4-5 days, during which period the patient is strictly confined to bed with assistance for feeding and toilet purposes. In uncomplicated cases, early ambulation is started by the fifth or sixth day. In complicated cases, ambulation should be postponed. Passive physiotherapy to the limbs is carried out to prevent venous thrombosis. In the first few days only liquid diet is allowed. Later, soft foods are introduced.
Sedation: Mental and physical rest is achieved by the regular use of diazepam 2-5 mg three or four times daily. Oxygen is administered to all cases. It helps in relieving pain, prevent shock and reduce the incidence of arrhythmias. In most of the uncomplicated cases, the condition improves with rest, sedation and the prevention of complications.
Ambulation: From the fourth or fifth day, the patient is allowed to sit up for increasing periods and allowed to use the bedside commode. Gradually the activity is increased and by the 14th day, he is allowed to walk in the room.
Compulsory hospitalization, relief of pain, adequate bed rest, sedation and Ambulation sum up to be the only way myocardial infarction patients could be adequately taken care of. So, it is important this is taken note of, especially for family members having loved ones in this situation. Do not leave it to the Doctors alone!
A Clot Or Thrombus
Management of Complications
Management of Complications: All the life-threatening complications such as fatal arrhythmias, shock, cardiac failure and major thomboembolism are managed in the ICCU. In intractable cases, surgical measures such as replacement of the mitral valve, closure of ventricular septal defect or coronary artery surgery may be required as life-saving measures.
Anti-coagulant therapy: Anticoagulants like heparin, phenindione, coumarins or warfarin have been employed to prevent the risk of venous thromboembolism and mural thrombi. There is no full agreement on the use of anticoagulants even after several decades of their introduction. However, full dose anticoagulation is indicated in ventricular aneurysm, marked obesity, cardiogenic shock, low cardiac output states, and phlebothrombosis. It is started with heparin in doses of 10-15,000 units intravenously followed six hourly by 5,000 units. The optimum dose is adjusted by keeping the clotting time at 1.5-2.5 times the normal level. Heparin is withdrawn after the initial few days and anticoagulation is maintained by one of the oral drugs started at least 2 days before withdrawing heparin. Smaller doses are sufficient to prevent venous thrombosis and pulmonary thromboembolism. For this purpose, 5,000 units heparin is given subcutaneously once in 8-12 hours and continued till the patient is discharged from hospital. The oral anticoagulants commonly in use are phenindione (Phenylindanedione) in a dose of 50-100 mg/day, acenocumarin (2-4 mg/day) or warfarin sodium (5-7.5mg/day). The optimum dosage is determined by keeping the Quick’s one stage prothrombin time at 2.5 times the normal.
Adverse effects of anticoagulants include bleeding tendencies manifesting as hematuria, hematemesis, ecchymosis and bleeding from injection sites and allergic manifestations. The effects of heparin are shortlives and usually subside withint 12 hours of stopping the drug. Protamine Sulphate (1mg neutralizes 90-100 units of heparin) can be given as a specific antidote if bleeding is troublesome. The effect of oral anticoagulants can be reversed by the intramuscular injection of vitamin K1 in a dose of 10-50 mg.
Fibrinolytic therapy: Recently fibrinolytic agents have been shown to be of benefit in dissolving the clot formed in the coronary arteries. Urokinase or streptokinase is employed for this purpose. Systemic administration and local administration into the coronary artery after selective catherterisation have been employed by many centers. These methods are still experimental.
Limiting Infarct Size And Convalescence
Limiting the size of the infarct: Attempts have been made from time to time to limit the size of infarct by drug therapy. Proper rest, oxygenation and control of arrhtymias and shock help in preventing the extension of the infarct. In addition, drugs such as propanolol, nitrates and calcium channel blockers (Verapamil, nifedipine, etc) reduce the myocardial requirement of oxygen and thereby prevent further infarction.
Convalescence: The uncomplicated patient is made to get out of bed by the 5th or 6th day and slowly ambulated so that he walks for 30 minutes before discharge from hospital after 12-14 days. Ambulation is contraindicated in the presence of angina pain, postural hypotension and occurrence of ventricular ectopics during or soon after the exercise. A sub-maximal stress test may be done 6-12 weeks after infarction to assess the capacity for work and normal activity. The aim of rehabilitation is to send the patient back to work in the course of 4-6 weeks. Occupations which entail risk to themselves and others, such as flying of aircraft and driving buses and trains are forbidden.
© 2014 Funom Theophilus Makama