@kathigg When a person's heart is behaving and beating normally, in sinus rhythm, metoprolol at a even a low or a moderate dose might cause the rate to drop low, but also still cause the beats' contractions, themselves, to be weak and to lower blood pressure. Between the slow beats and the weak contractions, you might be headed for a .....header. A fall. Fainting. You want to avoid that like the plague. So, please contact your primary care provider in the morning and let that person know what you have learned about your heart rate. They should know you're on metoprolol. Let your cardiologist know as well. Between those two, one of them should help you to avoid trouble with low blood pressure.

@kathigg my protocol was Metropol ER 25 mg 1X day and 100 mg of flecainide 2X day every day for intermittent a fib. I get several episodes a year and sometimes they go on 24 hours and I really need the Metropole when I'm having an episode to get my heart rate down to about 110 from 160. When I was taking Metropol daily, I was using Metropol extended release and my blood pressure was dipping way too low like 90/45 and I was advised to just take the Metropol as needed when I get an AF episode. My protocol now is I am still on flecainide twice a day, and I take a Metropol TARTRATE 25 mg, the fast acting Metropol, and brings my heart rate down a lot sooner than the extended release did. I don't know if it's helpful, but metoprolol extended release on a daily basis dropped my blood pressure way too low so I take it only when I get AF now, and the tartrate version is extremely helpful lowering heart rate during an AF episode.