Have been on a low dose of Metoprolol for three years. This betablocker controls my arrythmia. Much prefer taking medication to having an invasive ablation procedure.

Most Beta Blockers are effective and safe, and Metoprolol is both. For those of us with Afib; my family doctor said mine is Paroxysmal, though that's the first time I heard that; the top part of the heart beats at a very fast rate, and in some people, that fast rate causes the ventricles to beat very fast as well. That's the form I have, known as Rapid Ventricular Response.

Fortunately, between the top of the heart - the Atrium, and bottom - the Ventricles, is the AV Node - the AtrioVentricular Node. This limits how fast the ventricles can beat in response to activity in the Atrium. BetaBlockers such as Metoprolol slow the passage of signals through the AV Node, reducing the rate the Ventricles Beat.

I take 200 mg Metoprolol in the morning, 25 mg Metoprolol Tartrate in the early afternoon, and 150 mg Metoprolol Succinate at night. This is approved of by my physician, and the pharmacy had to talk to him before they'd fill it, even though the prescriptions were in their hands, because it's not common to take the Succinate (long acting version) and Tartrate (shorter acting version) in one day.

Only the Tartrate version has been proven to reduce the chance of a 2nd Heart Attack, but I'm not sure why. It may be because the only research was done on the Tartrate.

But I'm taking a large dose of Metoprolol, plus various other medications, I've not had the problems some attribute to even a smaller dose.

So, it safely, when used as directed, slows your heart rate, reduces the Contractile force of your heart, and actually helps calm some people down by limiting the effects adrenaline has on your heart and in some cases, system.