How do anti-anginals relieve chest pain?

Anti-anginals relieve chest pain primarily by dilating coronary arteries. This mechanism helps increase blood flow to the heart muscle, improving oxygen supply to areas that may be deprived due to narrowed or blocked arteries. When the coronary arteries are dilated, there is a reduction in myocardial oxygen demand, which alleviates symptoms of angina, a type of chest pain caused by insufficient blood flow.

The dilation of coronary arteries is particularly important during times of increased cardiac workload or stress, where the heart requires more oxygen but may not be able to supply it due to vascular constriction. By counteracting this constriction, anti-anginals facilitate greater oxygen delivery and thus provide symptomatic relief from angina.

The other answer choices address mechanisms that either do not directly relieve angina or would exacerbate the issue rather than alleviate it. Factors such as reducing heart rate or increasing blood viscosity may impact overall cardiac function but are not the primary mechanisms through which anti-anginals relieve chest pain.