Bradycardia how low is too low

Well, as you've all showed, there's bradycardia and there's bradycardia, brought on by a myriad of causes. Some bradycardia is physiologic and may represent normal cardiac function in some individuals, other bradycardia may be pathologic and cause physiological havoc and lousy quality of life in the poor schmucks inflicted with this ( ask me how I know this). To sort all this out, guidelines to differentiate among the causes of bradycardia( and tachycardia in applicable cases) and determination of appropriate treatment methods have been put forth to aid diagnosticians in their best treatment of patients with these conditions. I don't think anyone would be happy just to throw pacemakers/CRT/defibrillators at everyone who visits a cardiologist with a complaint of bradycardia!

The table shown in this link ( Merck Manual) summarizes the 2019/2021 American College of Cardiology, American Heart Association, and the Heart Rhythm Society Guidelines for pacemaker placement.
https://www.msdmanuals.com/professional/multimedia/table/indications-for-permanent-pacemakers
And here's a second article that basically covers take home points in those guidelines:
https://www.acc.org/latest-in-cardiology/ten-points-to-remember/2021/08/31/18/37/2021-esc-guidelines-on-cardiac-pacing-esc-2021

Am 62 and get chest pain discomfort at 80 bpm try telling anyone around this place and get brushed off.

@marybird Very interesting. I was very fit in my past and an average resting heart rate of around 43 was normal.

It’s been many years since I’ve been that fit. My average resting heart rate moved to around 55 - 60.

Suddenly last year my average resting heart rate at times dropped as low as 35 and averaged 44. I’m walking daily with my young dogs for a hour and a half but certainly no elite athlete any more!!

I’ve had numerous tests including an MRI and a 48 hour Holter monitor. No apparent reason for the very low results 🤷‍♀️

The cardiologist says not to worry but just keep an eye on my smart watch monitoring and how I feel. So that’s what I’m doing. No pace maker for me!

@isadora2021 Wow, a resting HR average between 35 and 44 seems pretty darn low to me, though maybe with your athletic history with a HR average of 43, this is still ok for you. Though I agree with your cardiologist it's something to watch, and if you develop symptoms with that bradycardia it might be time to do something about that bradycardia.

I was told the same thing by my cardiologist when my bradycardia set in- to keep an eye on it, but it was generally ok if: 1) the low heart rates were asymptomatic, and 2) the heart rate rose appropriately with activity. This happened with me for a while, but as the heart rate went lower and stayed there for longer times, I became symptomatic, nearly passed out several times. Then it got to where no matter what I did, moderate to vigorous activity, my heart rate would not go past the low 50's- unless, of course, it went into tachycardia, and it seemed as though it was one or the other, no happy mediums. I didn't want a pacemaker either, but I consented to it and it wasn't till I had it for a while and realized I felt much better, that I had to admit I needed one.
Maybe you'll get lucky and will never progress to the point where you need that pacemaker, but if you do, it won't be the worst thing in the world!

@marybird Thank you for sharing that. I am happy to have a pacemaker if needed. I was surprised (disappointed even) when I was told I didn’t need one. That’s ok as long as I’m ok without it. I do get tired and I do have incidences of light headedness/dizziness. For the 1st time the other day while out walking without the dogs (no stopping to sniff!) my watch gave me a high heart rate warning. It was nearly 170. I usually can’t get above 145 at the most. So that’s very abnormal for me. I’m seeing my GP on Monday and will see if there’s a next step 🤷‍♀️ Thank you.

@isadora2021 There are additional steps that can be taken to determine the significance, and what can be done about your bradycardia, and tachycardia if that's a problem as well.

Might your GP refer you to a cardiologist, preferably a cardiac electrophysiologist (EP)? These docs are experts in the heart's electrical system, cardiac arrhythmias ( ack, they might even know how to spell that word right) and treatment of these conditions.
Your next steps might be getting another cardiac monitor, possibly one you wear for 2 weeks to 30 days, the longer you wear it the more likely it is to catch and record arrhythmias that may be infrequent. These monitors include instructions and a way to document any symptoms you may feel at the time you're feeling them.
A cardiologist ( especially an EP) can look at those monitor EKG readings and determine the type, time and duration of any abnormal arrhythmias that have occurred. They can even often tell the mechanism of some of those arrhythmias from looking at the EKGs, for instance, with bradycardia, those readings may show it's due to sinus bradycardia, pauses of varying lengths of time, heart block, or even an AV node junctional rhythm. Correlating these findings with symptoms recorded at the time of the bradycardia ( such as dizziness, shortness of breath, near-syncope or syncope) is presumptive evidence that the bradycardia is the cause of these symptoms. Symptomatic bradycardia is one of the justifications for a pacemaker.

An EP can also look at tachycardia episodes on those EKG readings and differentiate between
types, such as A-fib, A-flutter, sinus tachycardia, one of the AV node re-entry types atrial tachycardia, or ventricular tachycardia. Based on the type, frequency and duration of these, the doc determines whether a finding is benign, or needs treatment. They'll go from there to determine the best treatment for the arrhythmia, hopefully in consultation and input from the patient.
This of course, is predicated on the patients' arrhythmias showing up on that monitor report. They don't always rear their ugly heads while a patient is wearing a monitor, in that case, the findings will essentially be normal and the doc can't evaluate arrhythmias that aren't there. Doesn't mean you don't have those issues, and the docs know this, if you have ongoing issues the only thing you can do is to repeat the monitor testing again, although these days if you have a Smart Watch or Kardia mobile or other device that record EKGs you can get one when you're symptomatic and send it to your doctor for evaluation.

The other test that can be done to document another form of bradycardia- chronotropic incompetence ( inability of the heart rate to reach levels needed for activity by the patient) is to have a stress test. In a patient with chonotropic incompetence, the heart rate will fail to reach appropriate levels as the patients' exercise levels increase on a treadmill. Documented chronotropic incompetence is another indication for a pacemaker.

So I mentioned symptomatic bradycardia and chronotropic incompetence as conditions under which pacemakers may be recommended. Another indication is when the symptomatic bradycardia may be caused by a medication the patient is taking, for which there is no alternative medication or treatment for that condition. For example, many of the beta blockers cause lowering of the heart rate, sometimes significantly. But the patient needs that medication to control the arrhythmia and there are no other good options to do so. So a pacemaker can be implanted to control the bradycardia from this medication, and the patient can continue to take it with no fear that it will drive the heart rate down too much.

I hope this helps. Fingers crossed that you can get your issues investigated fully and end up with good answers, and the best treatment for those issues!