Test your medicine knowledge with the MKSAP challenge, in partnership with the American College of Physicians.

A 68-year-old man is evaluated for exertional chest pain of 3 months’ duration. He describes the chest pain as pressure in the midsternal area with no radiation that occurs with walking one to two blocks and resolves with rest or sublingual nitroglycerin. No symptoms have occurred at rest. Medical history is significant for myocardial infarction 3 years ago, hypertension, and hyperlipidemia. Medications are aspirin, metoprolol 25 mg twice daily, simvastatin, isosorbide dinitrate, and sublingual nitroglycerin as needed for chest pain.

On physical examination, temperature is normal, blood pressure is 150/85 mm Hg, pulse rate is 80/min, and respiration rate is 12/min. BMI is 26. No carotid bruits are present, and a normal S₁ and S₂ with no murmurs are heard. Lung fields are clear, and distal pulses are normal.

Electrocardiogram shows normal sinus rhythm, no left ventricular hypertrophy, no ST- or T-wave changes, and no Q waves.

Which of the following is the most appropriate management?

A: Add diltiazem
B: Add ranolazine
C: Coronary angiography
D: Increase metoprolol dosage

MKSAP Answer and Critique

The correct answer is D: Increase metoprolol dosage.

This patient with coronary artery disease (CAD) and continuing angina should have his medical therapy optimized by increasing his dosage of β-blocker. Physical examination is notable for a blood pressure and heart rate that would allow further up-titration of the β-blocker. The β-blocker dose is adjusted to achieve a resting heart rate of approximately 55 to 60/min and approximately 75% of the heart rate that produces angina with exertion.

Calcium-channel blockers are first-line antianginal therapy in patients with contraindications to β-blockers. In patients with continuing angina despite optimal doses of β-blocker and nitrates, a calcium-channel blocker may be added. A calcium-channel blocker such as diltiazem is not indicated in this patient because his dosage of metoprolol is not yet optimal.

Ranolazine should be considered in patients who remain symptomatic despite optimal doses of β-blockers, calcium-channel blockers, and nitrates. Ranolazine is metabolized in the liver by the cytochrome P-450 system and its use is therefore contraindicated in patients with hepatic impairment, those with baseline prolongation of the QT interval, and those taking other drugs that inhibit the cytochrome P-450 system. Diltiazem and verapamil increase serum levels of ranolazine, and combined use of ranolazine with either of these agents is contraindicated.

Coronary angiography would be indicated if the patient was on maximal medical therapy with continued angina symptoms that were affecting his quality of life. Referral for coronary angiography is not indicated because the patient is not currently receiving optimal medical therapy.

Key Point

• In the treatment of chronic stable angina, the β-blocker dose is adjusted to achieve a resting heart rate of approximately 55 to 60 beats/min and approximately 75% of the heart rate that produces angina with exertion.

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