I Have A Patient With Her Normal Base Line Heart

I have a patient with her normal base line heart rate at 55 to 62 beats per second. recently in the past week and 1/2 her heart beat tends to indicate an arrhythmia as low as 58 up to 82 beats per second. she is 85 years old, diabetic(Mild) not insulin dependent metformin janeuvia, is cortisone dependent for COPD and Asthma Dexamethazone 0.75 mg/per day, takes lisinopril for blood pressure 10 mg daily. She has UTI and is on Augmentin antibiotic.
What could be the cause of the Arrythmia that is not going away?