Correct Answer: B

Rationale: Bradycardia is a common sign of digoxin toxicity. Digoxin can cause disturbances in the heart's electrical conduction system, leading to a slower heart rate. Therefore, the nurse should closely monitor the client's heart rate for signs of bradycardia, which could indicate digoxin toxicity.

Correct Answer: A

Rationale: Taking digoxin at the same time each day is essential to maintain a consistent blood level of the medication. This consistency helps optimize the therapeutic effects of digoxin in managing chronic heart failure. Deviating from the scheduled time could lead to fluctuations in drug levels, affecting its effectiveness and potentially causing harm.

Correct Answer: A

Rationale: Taking aspirin with food is recommended to prevent gastrointestinal irritation and upset, which are common side effects of aspirin. It helps to protect the stomach lining and reduce the risk of developing ulcers. This instruction is crucial in promoting medication adherence and minimizing discomfort for the patient.

Correct Answer: C

Rationale: The correct instruction for the client before a stress test is to wear loose, comfortable clothing, and walking shoes. This is crucial as the stress test involves physical exercise, and the client should be prepared for the activity involved. Beta-blockers may need to be adjusted or held before the test as per healthcare provider's instructions. Fasting before the test is not typically required, and avoiding physical activity for 24 hours beforehand is not necessary and may interfere with the accuracy of the test results.

Correct Answer: B

Rationale: Prothrombin time (PT) and international normalized ratio (INR) are crucial laboratory values to monitor the effectiveness of warfarin therapy in clients with atrial fibrillation. These values help ensure that the client is within the therapeutic range and that the anticoagulant effect of warfarin is appropriate.