What does digitalis/digoxin do?

What does digitalis/digoxin do?

• A. Increases intracellular calcium by blocking calcium channels.
• B. Inhibits Na+/K+-ATPase, increasing intracellular calcium to improve cardiac contractility.
• C. Stimulates beta-adrenergic receptors to increase contractility.
• D. Increases Na+ influx to promote conduction.

Answer: (B)

Digoxin works by inhibiting the Na+/K+-ATPase pump in heart muscle cells. This raises intracellular sodium, which reduces the driving force for the Na+/Ca2+ exchanger to remove calcium from the cell. With less calcium extrusion, intracellular calcium increases, boosting the amount available for release during contraction and producing a stronger, more forceful heartbeat (positive inotropy). Additionally, it enhances vagal tone, which slows conduction through the AV node and helps with rate control in conditions like atrial fibrillation. It does not act by blocking calcium channels, stimulating beta-adrenergic receptors, or increasing Na+ influx to promote conduction.

Digoxin works by inhibiting the Na+/K+-ATPase pump in heart muscle cells. This raises intracellular sodium, which reduces the driving force for the Na+/Ca2+ exchanger to remove calcium from the cell. With less calcium extrusion, intracellular calcium increases, boosting the amount available for release during contraction and producing a stronger, more forceful heartbeat (positive inotropy). Additionally, it enhances vagal tone, which slows conduction through the AV node and helps with rate control in conditions like atrial fibrillation. It does not act by blocking calcium channels, stimulating beta-adrenergic receptors, or increasing Na+ influx to promote conduction.