Final answer:
In case of an infant receiving digoxin with an apical heart rate of 80 bpm, the nurse should reassess the heart rate in 30 minutes to determine the stability and whether further interventions are needed. Option 3.
Step-by-step explanation:
An infant receiving digoxin for congestive heart failure has an apical heart rate of 80 beats per minute (bpm). In this medical scenario, the appropriate nursing intervention is to reassess the heart rate in 30 minutes. While bradycardia is defined as a heart rate below 60 bpm in adults, infants have different normal heart rate ranges, and 80 bpm can be considered normal depending on the age and clinical situation of the infant. However, if the heart rate is lower than the expected range for the infant's age, especially on digoxin therapy, close monitoring is required. Digoxin immune Fab is used in cases of digoxin toxicity, which is not indicated by heart rate alone. Obtaining a portable chest radiograph is not directly related to monitoring digoxin effects. A therapeutic drug level can be helpful but would not be the immediate next step before reassessing. The nurse should reassess the heart rate in 30 minutes to confirm whether the rate is stable, improving, or declining, which will guide further interventions. Option 3.