A 67 year old female presents to her primary care provider with 2 week history of palpitations. Her past medical history is significant for hypertension, diabetes, and heart failure. Her medications include lisinopril, carvedilol, furosemide, metformin, and warfarin. Which of the following medications should be added to control ventricular rate?
1) Amlodipine
2) Digoxin
3) Atorvastatin
4) Aspirin