42-year-old man with acute myocardial infarction, now pain free, with frequent premature atrial contractions, heart rate 80/min; blood pressure 120/70 mm Hg → intravenous propranolol.
+67-year-old woman with a history of congestive heart failure, now with mild breathlessness; takes “heart pill and water pill”; heart rate 100/min; blood pressure 100/70 mm Hg; cardiac monitor shows junctional tachycardia → intravenous digitalis.
+52-year-old man with acute anterior myocardial infarction, allergy to meperidine and morphine, continued pain; heart rate 90/min; blood pressure 130/90 mm Hg → intravenous pentazocine.
+60-year-old woman with acute myocardial infarction, hemodynamically stable → oxygen by nasal cannula at 4 L/min.
+45-year-old man with acute anterior myocardial infarction, heart rate 100/min; blood pressure 170/110 mm Hg. One minute after fibrinolytic infusion begins, heart rate 48/min; blood pressure 80/50 mm Hg → intravenous atropine.
Nitroglycerin is of benefit in treating a patient with an acute ischemic coronary event, and oral doses may be given repetitively at 3- to 5-minute intervals as needed as long as systolic BP is greater than 100 mm Hg (120 in hypertensive patients). Intravenous nitroglycerin is started at 10 μg/min and titrated to symptoms. Oxygen should be used at 4–6 L/min. Asymptomatic PACs and junctional tachycardias do not require treatment. Pentazocine elevates preload/afterload, decreases contractility, increases oxygen demand, and should not be used in patients with acute MI.