A. Decreasing heart rate which decreases oxygen demand

B. Decreasing contractility which decreases oxygen demand

C. Lowering blood pressure which decreases LV pressure in turn decreasing wall stress which decreases oxygen demand.

D. Increasing oxygen supply via arterial vasodilation

Beta-blockers antagonize beta receptors inhibiting the actions of the sympathetic nervous system reducing heart rate, contractility and blood pressure thus significantly decreasing oxygen demand  (see review of Beta Blockers). They are quite effective to relieve angina symptoms. Titration to achieve a heart rate of about 60 beats per minute is frequently required for optimal relief of angina. Common beta-blockers used are metoprolol, atenolol, propranolol and carvedilol.