Q. A 69-year-old woman presents to the emergency department complaining of dizziness with palpitations. During her intake, she experiences two episodes of light headedness with near syncope. Physical examination reveals palpitations and slight bradycardia. She is accompanied by her son, who states the patient is taking a medication for “her weird heart,” but neither he nor his mother can remember its name. Results of ECG are shown in the image. Which of the following medications is this patient likely taking that could both explain her symptoms and produce the abnormalities shown in this ECG?