Management of Myocardial Infarction

What is Myocardial Infarction?

Myocardial Infarction is defined as the ischaemic necrosis of a portion of the myocardium due to sudden occlusion of a branch of coronary artery according to the medical definition which can be simplified if these two words are explained alone; Ischemia means inadequate blood supply to the cardiac muscles where necrosis defines the death of cardiac muscle cells due to ischemia.

 

FIGURE 1. depicting the cardiac cell death due to MI

This is nothing less than heart attack because the impact of this particular disease is so intense that clearly states, according to the survey, 1/4 patients die before the therapy could be initiated. The management of MI is carried out by evaluating haemodynamic parameters, biochemical markers and ECG for selection of drugs and its dosage.

Drug Therapy in Myocardial Infarction

1. Pain, anxiety and apprehension: if pain is not relived by 3 doses of GTN given 5 minutes apart, an opoid analgesic (morphine/pethidine)or diazepam is administered parenterally. 
2. Maintenance of blood volume, tissue perfusion and microcirculation: Slow i.v. infussion of saline/low molecular weight dextran is carried out to avoid volume overload. 
3. Prevention and treatment of arrhythmias:Prophylactic i.v. infusion of a Beta blocker in immediate MI patient and its continuation orally for a few days has been shown to reduce the incidence of arrhythmias and mortality. 
4. Pump failure: to increase cardiac output and/or decrease filling pressure without unduly increasing cardiac work or loweing BP. Drugs are used for this purpose are given in chart. 
5. Prevention of thrombus extension, embolism, venous thrombosis: Aspirin (162-325 mg) should be given for chewing and swallowing in immediate MI patient. This is continued at 80-160 mg/day. 
6. Thrombolysis and reperfusion: Plasminogen activators such as streptokinase, urokinase, alteplase to achieve reperfusion of infarcted area. 
7. Control of hyperlipidemia: dietary substitutes with unsaturated fats, hypolipidemic drugs etc.