My Mom has Afib and heart rate has been high for last 2 or 3 days. She is on Amiodarone, Metoprolol, Coumadin, Lasix, Spironolactone and Potassium, Advair and Sporiva. Blood pressure has been around 120/85. She continually sits with a heating pad to her back. Could the heating pad be the cause of her heart rate being high. It has been ranging from 87 to 105 for the past few days. She is 90 years old.