A nurse is caring for a client who has angina and reports a feeling of heaviness in the chest while ambulating in the hall. Which of the following actions should the nurse take first?

A. Obtaining an ECG is important to assess for myocardial ischemia, but it is not the first action. The nurse must first relieve myocardial oxygen demand by stopping activity. B. Nitroglycerin administration is appropriate after the client has been seated and activity stopped, ensuring safety and stable positioning in case of hypotension. C. The priority action is to stop activity and have the client sit down to decrease oxygen consumption and cardiac workload. This helps prevent further ischemia and possible infarction. Once resting, further assessment and interventions can proceed safely. D. Measuring vital signs provides useful data but should be done after stopping the client’s activity. The immediate need is to reduce cardiac demand.