Non-dihydropyridine calcium-channel blockers, such as diltiazem (Cardizem) and verapamil (Calan), should generally NOT be used in which of the following conditions?

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Accepted Answer

✅ C. Heart failure with reduced ejection fraction (HFrEF)
Non-dihydropyridine CCBs (diltiazem, verapamil) are potent negative inotropes and negative chronotropes. In a patient with reduced systolic function, suppressing contractility further can worsen heart failure, precipitate decompensation, and increase mortality. They are therefore contraindicated (or at minimum strongly discouraged) in HFrEF. Dihydropyridine CCBs amlodipine and felodipine are the only CCBs considered safe in HFrEF because they act primarily on vascular smooth muscle with minimal direct myocardial depression.

❌ A. Atrial fibrillation with rapid ventricular response and preserved EF
This is actually a primary indication for diltiazem or verapamil. Non-DHP CCBs are first-line for rate control in a-fib with RVR when the patient has preserved ejection fraction. IV diltiazem is commonly used for acute rate control.

❌ B. Stable angina pectoris
Non-DHP CCBs are an appropriate therapy for chronic stable angina, particularly in patients who cannot tolerate beta-blockers. They reduce myocardial oxygen demand through negative inotropy and chronotropy plus coronary vasodilation.

❌ D. Hypertension in a patient intolerant of ACE/ARB
Non-DHP CCBs are an acceptable antihypertensive option in patients with normal systolic function who cannot tolerate ACE inhibitors or ARBs. They are especially useful when concurrent rate control or anti-anginal effect is desired.

:::danger
Key safety rule: Never combine a non-DHP CCB (diltiazem, verapamil) with a beta-blocker in a patient with LV dysfunction. The combined negative inotropic and chronotropic effects can cause severe bradycardia, AV block, hypotension, and cardiogenic shock. In HFrEF, use amlodipine if a CCB is absolutely needed.
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