Heart palpitations

I've been having periodic heart palpitations for a little over a year now. I have been diagnosed to have coronary artery disease. I also take levothyroxine for the thyroid I had removed due to cancer in 2019. My cardiologist says it's because of not the right dosage. So, between him and my Endocrinologist we change doses periodically. I'm resting today because of palpitations I had last night. Heart rate sitting was 139. This is very frustrating and scary. I'm wondering if my cholesterol medicine has anything to do with this? I'm at a loss...