Which substance is a cardiac glycoside used to improve contractions in heart failure?

Which substance is a cardiac glycoside used to improve contractions in heart failure?

• A. Digoxin
• B. Morphine
• C. Atropine sulfate
• D. Calcium chloride

Answer: (A)

Cardiac glycosides boost the heart’s pumping strength by inhibiting the Na+/K+ ATPase pump in cardiac cells. This raises intracellular sodium, which slows the Na+/Ca2+ exchanger, allowing more calcium to remain inside the cell, and the extra calcium makes the heart squeeze more forcefully. That is why digoxin is used to improve contractions in heart failure. The other drugs don’t share this inotropic mechanism: morphine reduces pain and preload but doesn’t increase contractility; atropine sulfate increases heart rate by blocking parasympathetic influence rather than strengthening contraction; calcium chloride provides calcium but is not a cardiac glycoside and isn’t used for this purpose in heart failure.

Cardiac glycosides boost the heart’s pumping strength by inhibiting the Na+/K+ ATPase pump in cardiac cells. This raises intracellular sodium, which slows the Na+/Ca2+ exchanger, allowing more calcium to remain inside the cell, and the extra calcium makes the heart squeeze more forcefully. That is why digoxin is used to improve contractions in heart failure. The other drugs don’t share this inotropic mechanism: morphine reduces pain and preload but doesn’t increase contractility; atropine sulfate increases heart rate by blocking parasympathetic influence rather than strengthening contraction; calcium chloride provides calcium but is not a cardiac glycoside and isn’t used for this purpose in heart failure.