Final answer:
The nurse should auscultate the apical pulse for 1 minute before administering digoxin to ensure the patient's heart rate is within a safe range to prevent potential complications.
Step-by-step explanation:
Before administering digoxin to a client with an irregular heart rate, the most important action for the nurse to take is to auscultate the apical pulse for 1 minute. This is crucial because digoxin affects the electrical activity and the contractility of the heart. Ensuring the apical pulse is within a safe range before administration helps to prevent potential complications, such as digoxin toxicity, which can further impair the heart's rhythm and function. Auscultation is a simple yet effective diagnostic technique used to assess the state of the patient's heart. If the apical pulse is too low, it may be unsafe to give the medication, and the healthcare provider should be informed.