Which medication increases cardiac output in heart failure?

• A. Diuretics
• B. Beta blockers
• C. Digoxin
• D. ACE inhibitors

Answer: (C)

Increasing cardiac output in heart failure is achieved by boosting the heart’s ability to contract, so more blood is ejected with each beat. Digoxin does this directly: it inhibits the Na+/K+ ATPase pump in heart muscle cells, which raises intracellular calcium during systole. The extra calcium strengthens the heart’s contractions, increasing stroke volume and, therefore, cardiac output. It also slows conduction through the AV node, which can help control rapid heart rates and improve how well the ventricles fill, further supporting forward flow in suitable patients.

Relief of fluid overload with diuretics lowers preload and reduces symptoms, but it doesn’t raise the forward pumping capacity. Beta blockers decrease heart rate and contractility (at least initially), which can lower cardiac output until long-term remodeling occurs. ACE inhibitors reduce afterload, aiding forward flow, but their primary effect isn’t an increase in contractility.