Cardiac medication used to help with cardiac contractility after you have optimized most of the other cardiac medications?

• A. Atenolol
• B. Captopril
• C. Digoxin
• D. Furosemide

Answer: (C)

After optimizing the standard heart failure therapies, some patients still have symptoms from reduced pumping ability, so a medication that directly increases the strength of each heartbeat can be helpful. Digoxin does this by inhibiting the Na+/K+ ATPase in cardiac muscle cells, which raises intracellular calcium during systole and boosts contractile force. It also provides some rate control by increasing vagal tone, which can help if atrial fibrillation is present. This makes it a useful additive for symptom relief and exercise tolerance in patients whose condition remains symptomatic despite optimized medications. However, it doesn’t clearly improve survival and has a narrow therapeutic window, so monitoring renal function, electrolytes (especially potassium), and potential drug interactions is essential to avoid toxicity.

Atenolol is a beta-blocker that reduces heart rate and contractility (longer-term mortality benefit comes from improved remodeling and sympathetic modulation, not from increasing contractility). Captopril lowers afterload and improves remodeling but doesn’t directly boost contractile strength. Furosemide reduces fluid overload without affecting the heart’s pumping force.