Q & A With the Expert on: Coronary Artery Disease Management of an Older Person With Unrecognized Q-Wave Myocardial Infarctio

Q: A 73-year-old asymptomatic woman with no history of myocardial infarction (MI) is seen by her physician. She is a nonsmoker. Her blood pressure is 150/80 mm Hg. Her heart rhythm is regular with a ventricular rate of 82 beats per minute. Her body mass index is 25 kg/m². Her physical examination is normal except for her blood pressure. A routine electrocardiogram shows evidence of an old anterior wall MI not present on a routine electrocardiogram obtained 1 year previously. A 2-dimensional echocardiogram shows a left ventricular ejection fraction (LVEF) of 39%. Her complete blood count, fasting blood sugar, and estimated glomerular filtration rate are normal. Her serum lipids show a total cholesterol of 194 mg/dL, a serum low-density lipoprotein (LDL) cholesterol of 120 mg/dL, a serum high-density lipoprotein (HDL) cholesterol of 50 mg/dL, and serum triglycerides of 120 mg/dL. She is not taking any medications. How should this patient be treated?

A: The prevalence of an unrecognized Q-wave MI in older persons detected by a routine electrocardiogram in ten studies¹ varied from 21%² to 68%³ of Q-wave MIs. In six studies, the incidence of new coronary events including recurrent MI, ventricular fibrillation, and sudden cardiac death in persons with unrecognized Q-wave MI was similar to (5 studies) or higher than (1 study) in persons with recognized Q-wave MI.^1,4,5 Therefore, postinfarction patients with unrecognized Q-wave MI should be treated similarly to postinfarction patients with recognized Q-wave MI.

Coronary risk factors must be treated intensively in older persons with prior MI.^6,7 The woman in the case above has isolated systolic hypertension, which should be treated with a low-salt diet and with a beta blocker plus an angiotensin-converting enzyme (ACE) inhibitor to reduce the systolic blood pressure to less than140 mm Hg.^6,8,9 If she had diabetes mellitus or chronic renal insufficiency, her systolic blood pressure should be reduced to less than 130 mm Hg.^6,8 This woman also has a high LDL cholesterol, which must be treated with a low-cholesterol, low-saturated-fat diet, and with a statin. Her serum LDL cholesterol must be reduced to less than 100 mg/dL, and optimally to less than 70 mm Hg.^6,7,10-12

Postinfarction patients should be treated with an antiplatelet drug, preferably low-dose aspirin.^6,7,13-15 I recommend using a 81-mg daily dose of aspirin since this dose has similar efficacy in reducing cardiovascular events and mortality to higher doses of aspirin with less bleeding.¹³ Postinfarction patients should be treated with a beta blocker (metoprolol, carvedilol, propranolol, or timolol) and an ACE inhibitor to reduce cardiovascular events and mortality, especially if the patient has a reduced left ventricular ejection fraction (LVEF), as this woman has.^6,7,9,16-23 This woman needs to be treated with a beta blocker plus an ACE inhibitor because she has a prior MI, a reduced LVEF, and isolated systolic hypertension.

Finally, this asymptomatic older woman should have a treadmill stress test, especially because of her reduced LVEF, since she is at increased risk for cardiovascular events and mortality.^1,7 If she has stress test–induced myocardial ischemia, further investigation is indicated.^1,7 The treadmill stress test should be performed before starting a physical exercise program.^1,6,7,24

Influenza immunization with inactivated vaccine administered intramuscularly is recommended as part of secondary prevention in persons with coronary artery disease or other atherosclerotic vascular disease.^6,25