For which condition is digoxin primarily prescribed?

Digoxin is primarily prescribed for heart failure due to its ability to increase the force of myocardial contractions, which enhances cardiac output. In patients with heart failure, the heart struggles to pump sufficient blood to meet the body’s needs. Digoxin works by inhibiting an enzyme known as Na+/K+ ATPase, which leads to an increase in intracellular calcium levels, improving contractility. This is particularly beneficial for patients with systolic heart failure, where the heart's pumping function is compromised.

While digoxin can also have a role in managing atrial fibrillation—primarily to control the ventricular rate—it is not its primary indication. It is not used for treating hypertension or asthma, as these conditions require different therapeutic approaches. Therefore, the correct choice focuses on the primary use of digoxin in managing heart failure.