What is the primary indication for diltiazem in the management of cardiovascular conditions?

A. To treat hypertension and angina: Diltiazem is a calcium channel blocker that relaxes vascular smooth muscle and decreases myocardial oxygen demand, effectively lowering blood pressure and relieving angina. It is commonly prescribed for both conditions as a first-line therapy. B. To prevent thromboembolism: Diltiazem does not have anticoagulant or antiplatelet effects and therefore does not prevent thromboembolic events. Other medications, such as warfarin or antiplatelet agents, are used for this purpose. C. As an antiarrhythmic agent: Although diltiazem can slow atrioventricular conduction and may help control some arrhythmias, this is a secondary effect rather than its primary indication. Its main use remains in hypertension and angina management. D. To manage heart failure: Diltiazem is generally not used for heart failure because negative inotropic effects can worsen cardiac output in patients with reduced ejection fraction. Other drug classes, such as ACE inhibitors or beta-blockers, are preferred for heart failure management.