Digitalis is primarily used to treat which condition?

Digitalis, particularly in the form of digoxin, is primarily utilized to treat atrial fibrillation. This condition is characterized by an irregular and often rapid heart rate that can lead to various complications such as stroke and heart failure. Digitalis works by increasing the force of myocardial contraction (positive inotropic effect) and helping to regulate heart rate by slowing down conduction through the atrioventricular (AV) node. This is particularly beneficial in atrial fibrillation, where it helps control the ventricular rate, ultimately improving cardiac function and reducing symptoms.

The other conditions listed have different primary treatments. For example, angina is primarily managed with antianginal medications, although digitalis can sometimes be used in more complex cases. Hypertension is typically treated with a variety of antihypertensives that focus on reducing blood pressure, and thrombus formation is usually addressed with anticoagulants or antiplatelet medications. Therefore, the specific action of digitalis aligns best with the management of atrial fibrillation, making it the correct choice.