A client with suspected angina pectoris is scheduled for a coronary angiography. The client asks the nurse about the purpose of the test. How should the nurse respond?

A) This choice is incorrect because furosemide is a loop diuretic used to treat fluid retention and edema in clients with congestive heart failure (CHF), but it does not directly reduce myocardial oxygen demand.

B) This choice is correct. Metoprolol is a beta-blocker that reduces heart rate and blood pressure, resulting in decreased myocardial oxygen demand. It is often prescribed to clients with an MI and a history of CHF to improve cardiac function and reduce the workload on the heart.

C) This choice is incorrect because aspirin is an antiplatelet medication that prevents further clot formation and is commonly prescribed in clients with acute coronary syndrome, including MI. While it is beneficial in the context of MI management, it does not directly reduce myocardial oxygen demand.

D) This choice is incorrect because nitroglycerin is a vasodilator used to relieve chest pain (angina) by dilating blood vessels and increasing blood flow to the heart muscle. While it helps reduce anginal symptoms, it does not directly reduce myocardial oxygen demand as metoprolol does.

A: Oxygen does not directly dilate coronary arteries; medications such as nitrates are responsible for this effect.
B: While oxygen aids in metabolic processes, it does not directly affect the heart's pumping efficiency in the context of angina pectoris.
C: Oxygen therapy increases the oxygen saturation of the blood, which can help alleviate symptoms like shortness of breath and chest pain associated with angina by ensuring that the heart muscle receives sufficient oxygen to function properly.
D: Oxygen therapy is not a treatment for preventing clot formation; this is typically managed with anticoagulant medications.