Which antiarrhythmic is contraindicated in decompensated heart failure?

• A. Amiodarone
• B. Diltiazem
• C. Dronedarone
• D. Flecainide

Answer: (C)

In decompensated heart failure, the heart’s pumping ability is already compromised, so we avoid antiarrhythmics that can worsen heart function or increase mortality. Dronedarone is contraindicated in this setting because studies and regulatory labels showed it raises cardiovascular mortality and can precipitate or worsen heart failure in patients who are decompensated. Even though it was designed to be safer than amiodarone, the risks outweigh benefits when the heart is failing acutely, so it should not be used.

Amiodarone, by contrast, has a more favorable hemodynamic profile in heart failure and is commonly used in patients with HF, including during decompensation, under careful monitoring. Diltiazem carries a risk of negative inotropy and hypotension, which makes it undesirable for rhythm control in decompensated HF, though it may be considered in other, more stable contexts. Flecainide is proarrhythmic in the presence of structural heart disease and LV dysfunction, so it is also avoided in decompensated HF, but the explicit contraindication cited in guidelines and labeling is dronedarone.