@bohaiboy Flecainide is a sodium channel blocker that helps to keep the heart in rhythm. It also has a mild analgesic or anesthetic effect on the body. It is not a rate control medication the same way diltiazem or metoprolol are...those two are definitely calcium channel and beta-adrenergic receptor medications respectively that do help to keep a lid on the rate. The metoprolol never did work well for me. It neither kept me out of rhythm, even though it does have a mild rhythm control aspect to it, but when I did fibrillate it couldn't control my rate. I was typically above 140 BPM, indicating 'RVR', or 'rapid ventricular response'. If your rate is below 100, it means you do not appear to have a typical RVR. Good for you!