My oncologist initially thought A/C may have caused my AF, but changed his mind. My cardiologist thought a combination of surgery and chemo caused it, but also changed his mind, mainly for the same reason, no improvement when chemo
ended. But it has improved, ever so slowly, over the years, so who
knows. I also acknowledge that AF is the most common form of arrhythmia in those over 65, so there may have also been a compounding age issue. But Metoprolol has been an effective and simple way of controlling my heart rate which also has improved my heart rhythm. With no side effects that I know of!