Basic ? re beta blockers

Hi,

This question will sound dumb; nevertheless, I am confused about what beta blockers do with regard to BP vs heartrate. During my heart troubles, I did not tolerate metoprolol, the cardioselective beta blocker. I do tolerate carvedilol (Coreg) the non-selective beta blocker & it also helps my benign essential tremor of the hands.

Since I have been good with no arrhythmias for over a year, I am just on 6.25 mg b.i.d. of carvedilol. I am beginning to get back to some better thyroid replacement for my thyroidless state. Previous to my heart problems, I was on natural dessicated thyroid & no synthetic, but was placed on all synthetic when my arrhythmias started. Now, I am taking a mix of the two. I take the smallest dose size of NP Thyroid (which has the T3 in it as well as the other Ts) in the morn with my synthetic & I am trying to be very careful not to get into any heart trouble. I have done that successfully for a year though I felt tired in afternoons & really needed more thyroid replacement. Six weeks ago we allowed me to take the NP dose in the morn & afternoon on 3 days a week.

That was all background for my question here: Sometimes my heartrate (if that is what we call pulse, I think) gets up to 87, and I feel a little like I used to with afib - racy, heart slightly thudding, tired. I have never been a person with a low heartrate generally anyway. I keep taking a Kardia EKG when I feel that & all is okay with no arrhythmia. My cardiologist (who I no longer see for over a yr, since I have been off all his meds) told me in the past that if BP gets low, pulse can get high to compensate - I am not sure if he said that was always the case or just that it could be a reason if one of those two gets high, the other gets low. Sometimes when I get the high pulse, my BP will only be in double digits, but not frighteningly low, the systolics get too low ranging from 87 to 98 (4 times in July looking thru my machine), but the diastolics aren't as below range at 63 to 68 during July. Most of the rest of the time, my BP is good & pulse can be in 70s or 80s.

Now that we have upped my thyroid dose a bit, I have been given another script of carvedilol 3.125 mg to add in a few times a week if I feel I need it. I do not really have a BP problem. What I want is to keep my rate (?pulse) lower & also keep my hand tremor down as 6.25 BID can do pretty well. I am thinking I might keep the overall total daily dose of 12.5 mg the same, but split it up differently. As usual take my 6.25 in morn, then at lunch on MWF when I take extra NP Thyroid, take 3.125 of my carvedilol at the same time, then at night instead of my usual 6.25, just take another 3.125 so I keep my daily total 12.5, but weight it more toward the daytime when my natural dessicated thyroid is activating my heart more.

I certainly am nowhere near any kind of heart failure (which I read is the main reason to prescribe carvedilol), but for some reason it agrees with me very well where the metoprolol did not at all. I do not want my heart to weaken though by taking this drug more than I need it. Does it sound safe to take extra when I feel my heart racing too much for too long & will it actually lower my pulse or my BP too? Like I say, mostly if I get the high pulse my BP goes down to double digits, so it is confusing to me whether I need extra carvedilol at that time or not.

I have written my endocrinologist a letter & mailed it today to see what he thinks. He was an internist before he became an endocrinologist. He is a good doctor & he does listen to what I bring to him & we work together. The cardiologist was way stricter & wanted to keep me on all his meds despite my need for them & I felt so much better by the time we parted ways with me trusting that his meds were making me feel worse & that I did not need them anymore. I knew from the first electrophysiologist who told me the meds could make me worse or better. I finally got well enough to not need them - I believe they were actually causing me flutter at the time.

I should tell you I had my Natale ablation August 2019 & it took me several months to get completely free of flutter - past the blanking period, but I finally got free & medicine free as far as antiarrhythmics & blood thinners.

For a sample, I took my BP/pulse about 15 minutes ago & it was 108/75, 85 pulse.

Sorry my post is so detailed, but can you at least explain to me about my beta blocker use & what it does to BP or pulse & tell me if it sounds like I am doing a safe thing & not making my heart too dependent on this drug. Does my plan sound good?

Thank you in advance.

You're waaaaay over analyzing this.

Yes, it's true that a low BP can cause a rapid heart rate. That happens when your body can't get your BP back up so it speeds up the HR to compensate so it can deliver enough blood to your body. An example of when this might happen is when you simply don't have enough blood volume from things like severe blood loss or dehydration. It's your body's reaction to something very severe. It's not like some formula that says if your BP goes down your HR goes up and vice versa even when nothing's wrong. Basically, forget what he said. It simply doesn't apply to you.

As for beta blockers, they do two things: They lower your BP and they also lower your HR. This reduces the work load on your heart, so that's why they're almost always prescribed to patients with heart attacks, heart failure, etc. They're prescribed to people who only have afib, flutter, etc. only for their ability to reduce the HR. Nothing else. If you have hypertension with or without afib, they might also be prescribed to lower your BP. I also take carvedilol for BP but I don't have afib, so it's only for the BP reducing qualities.

Anyway, like I said, you're overanalyzing this. I didn't hear anything that sounded like an actual problem. Your BP is perfectly fine and your HR is probably elevated by the thyroid meds, but it's not high enough to worry about. Relax.