Which of the following is an immediate nursing intervention for a patient experiencing angina pectoris due to coronary artery disease?

Angina pectoris results from transient myocardial ischemia caused by an imbalance between myocardial oxygen supply and demand, most commonly due to coronary artery atherosclerosis and vasoconstriction. This leads to chest pain without myocardial necrosis, requiring rapid restoration of coronary blood flow and reduction of cardiac workload. Rationale: A. Providing dietary education is important for long-term management of coronary artery disease but does not relieve acute myocardial ischemia or chest pain. It is a preventive, not immediate, intervention. B. A stress test is a diagnostic procedure used to evaluate cardiac function under exertion. It is not appropriate during an acute angina episode and does not provide immediate symptom relief. C. Nitroglycerin is a vasodilator that relaxes coronary smooth muscle, improves coronary blood flow, and reduces myocardial oxygen demand by decreasing preload. It provides rapid relief of anginal pain and is the first-line immediate intervention. D. Exercise increases myocardial oxygen demand and can worsen ischemia during an angina episode. Physical activity is contraindicated during acute chest pain and should only be introduced in a controlled rehabilitation setting.