Mike, I pray that this surgery went well. I pray you have had a full recovery and are strong in the Lord and the power of His might!
My heart palpitations were helped by an Ayurvedic herb called Arjuna. They were also helped by green tea. Another thing you can do is buy capsules containing ground up beef heart from grass fed cows. Have you tried any of the following? Ayurveda. Traditional Chinese medicine. Naturopathy. Integrative medicine. These four branches of health sure helped me. Some medical doctors (M.D.s) practice integrative medicine. You can find one on IFM.org I don't know if any of these things will help an irregular heartbeat or not. My problems might not be the same as what you are. But here is the information in case you can use it. You can look into it yourself. Good luck
Father, we pray for Mike to have successful knee surgery and for a regular heart rhythm. We pray for peace for his soul. AMEN!