MYOCARDIAL INFARCTION

A 63-year-old white male presents to the ER with sudden onset of severe retrosternal chest pain associated with nausea, vomiting and diaphoresis. His EKG shows ST segment elevation in leads aVL and I. The patient was treated with thrombolytic therapy in the ED. He is known to have insulin requiring diabetes mellitus for the past 3 years as well as hypertension for the past 2 years. His medications include insulin and enalapril. Which of the following set of medications has been shown to reduce mortality after an acute MI?

A. Nitrates, beta blockers, and aspirin
B. ACE inhibitors, nitrates, and beta blockers
C. Magnesium, beta blockers, and aspirin
D. Oxygen, morphine, aspirin, and nitrates
E. Aspirin, beta blockers, and ACE inhibitors

the answer is E. Aspirin, beta blockers, and ACE inhibitors

Explanation:
Of all the above choices, only ACE inhibitors, aspirin, and beta-blockers have been shown to reduce mortality after acute MI.

The proposed mechanism for ACE inhibitors is the reduction of ventricular remodeling and thus reduced incidence of left ventricular dysfunction / aneurysmal dilatation after MI. They are recommended in all patients of acute MI with CHF as well as to those who are hemodynamically stable and have ST segment elevation or left bundle branch block. They are usually started within the first 24 hours of acute MI and are continued indefinitely in those who have CHF, HTN or LV dysfunction.

Aspirin has also been shown to be effective and should be given in all patients, as early as possible in the setting of an acute MI, because it has been shown to reduce mortality by as much as 30%.

3 doses of IV beta-blockers, followed by oral beta-blockers in doses titrated for a heart rate of 50-60, have also been shown to reduce the mortality significantly in acute coronary syndromes.

Morphine is an effective analgesic and is used for pain relief in the setting of an acute MI. Oxygen is useful only when pulse oximetry shows hypoxemia. Its routine use in all patients of acute MI is not cost effective. Nitrates are used only for pain relief in the setting of acute MI and they don’t incur any survival advantage. IV nitrates should be avoided when there is hypotension or evidence of right ventricular infarction. IV magnesium is indicated only when initial testing shows low serum magnesium level. Routine use of IV magnesium in all MI patients does not provide any survival benefit.