Final answer:
For a patient with a new arrhythmia, the best discharge instruction by the nurse would be to encourage the patient's family and friends to learn CPR, and understand the usage of AEDs, due to the potential emergencies that can arise with abnormal heart rhythms.
Step-by-step explanation:
The nurse providing discharge instructions for a patient with a new arrhythmia should include education on the importance of understanding the condition, how to manage it, and when to seek immediate medical attention. The correct choice in the given options is: a) Your family and friends may want to take a CPR class. This is because knowing CPR (cardiopulmonary resuscitation) is beneficial in case of an emergency where the patient's heart has stopped and while awaiting professional medical help. Also, it's important to know how to use an AED (automated external defibrillator), devices often found in public places for the same reason. In contrast, the other options provided are incorrect as missing doses of medication should never be doubled up without consulting a physician, it is crucial for patients to know how to monitor their own pulse, and experiencing symptoms such as lightheadedness and dizziness should be taken seriously as they could indicate complications.