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

A 55-year-old man is evaluated during a routine examination. He has a 2-year history of nonischemic cardiomyopathy. (Echocardiogram 2 years ago demonstrated a left ventricular ejection fraction of 35%.) He is feeling well and reports no shortness of breath; he walks 2 miles daily without symptoms. Medical history is remarkable for hypertension. Medications are lisinopril, carvedilol, and chlorthalidone.

On physical examination, blood pressure is 150/90 mm Hg and pulse rate is 50/min. No jugular venous distention is present. Cardiac examination reveals a regular rhythm with no murmurs or gallops. Lungs are clear to auscultation. No edema is present.

Laboratory studies show serum creatinine level of 1.5 mg/dL (133 µmol/L), sodium level of 138 mEq/L (138 mmol/L), and potassium level of 4.0 mEq/L (4.0 mmol/L).

Electrocardiogram shows a normal sinus rhythm and left ventricular hypertrophy.

Which of the following calcium-channel blockers should be added to this patient’s medical regimen?

A: Amlodipine
B: Diltiazem
C: Nifedipine
D: Verapamil

MKSAP Answer and Critique

The correct answer is A: Amlodipine.

This patient with resistant hypertension (blood pressure not at target with three-drug therapy of different classes of drugs, including a diuretic) and systolic heart failure should begin taking the calcium-channel blocker amlodipine to improve control of his blood pressure. Although specific combinations of drugs have not been well studied in patients with resistant hypertension, many experts recommend adding a calcium-channel blocker to an ACE inhibitor and a diuretic when patients are not at their target blood pressure. The diuretic chlorthalidone has a long duration of action and may be more effective than hydrochlorothiazide.

Many calcium-channel blockers are relatively contraindicated in patients with systolic heart failure owing to an associated increased risk for precipitating heart failure exacerbation. Amlodipine and felodipine are newer-generation agents that have been demonstrated in large-scale clinical trials to have a neutral effect on morbidity and mortality. Because they are not associated with morbidity or mortality benefits, calcium-channel blockers are not first-line treatment for systolic heart failure. Use of calcium-channel blockers in systolic heart failure is generally reserved for treatment of conditions such as hypertension or angina that are not optimally managed with maximal doses of evidence-based medications such as ACE inhibitors and β-blockers.

Older generation calcium-channel blockers, such as diltiazem, nifedipine, and verapamil, may precipitate heart failure exacerbation owing to their negative inotropic effects. Although his symptoms are currently controlled (New York Heart Association class I), he would still be at risk of an exacerbation with one of these agents.

Key Point

• The calcium-channel blocker amlodipine is a reasonable option for additional blood pressure control in a patient with heart failure who is already receiving optimal multidrug therapy.

This content is excerpted from MKSAP 16 with permission from the American College of Physicians (ACP). Use is restricted in the same manner as that defined in the MKSAP 16 Digital license agreement. This material should never be used as a substitute for clinical judgment and does not represent an official position of ACP. All content is licensed to KevinMD.com on an “AS IS” basis without any warranty of any nature. The publisher, ACP, shall not be liable for any damage or loss of any kind arising out of or resulting from use of content, regardless of whether such liability is based in tort, contract or otherwise.