Answer:
ECG
Step-by-step explanation:
An ECG is appropriate to determine if her heart is working properly. Problems with her heart or her arterial pressure could have caused the loss of her visual field and that red spot in her eye. As she stated that she feels nervous and has lost weight, she may have hyperthyroidism, which is making her feel that way and has damaged her eye. The first step to check if hyperthyroidism has caused atrial fibrillation is an ECG.