What can cause the heart rate to drop during exertion?

SFCardiacRN · Jan 11, 2006

Listen to her doctor.

Dinith88 · Jan 13, 2006

I am an LPN in a LTC facility. I have a resident whose resting heart rate is always >100, but after PT her heart rate is dropping into the 80s. What could be the cause of this? I've reported it to her doctor, but he doesn't seem concerned. I feel it warrants further testing. I need some advise please!

Your concern is understandable...but the doctor is correct in not being worried. A heart rate in the 80's is normal...and if her heart rate is 'always 100's', thats probably not a concern either. The rate change is probably a result of medications given before therapy (most likely). Yes it's strange that a rate would drop after exercise, but if it's going from 'normal' to 'normal', you can better understand why it's not an issue. If the rate drops below 60 and/or is accompanied by symptoms (shortness of breath, dizziness, chest pain, etc.) then your doc might become a little more receptive to your reports/suggestions. Check her meds, and look for ones that would/could do this (digoxin, calcium channel blockers, beta-blockers, etc.) it may be the source of the rate change. Also, be aware that a rate in the 80's is actually preferable to one ine the 100's..even if the 100's is 'normal' for her. You may actually be reporting to the doc that her rates are 'better' than usual...

Hope this helps a little.

dawnb70 · Jan 14, 2006

Thank you for your help! I did a little research online and ran across an article from USA Today that stated that individuals whose heart rate drops during exertion are more likely to drop dead of a heart attack. I can't remember the details...I guess I just feel like I should be doing more for this resident. She's had generalized c/o malaise for several weeks, and we have been unsuccessfully trying to find the cause of it. I thought maybe I had found something with the dropping heart rate.

christvs, DNP, RN, NP · Jan 15, 2006

Thank you for your help! I did a little research online and ran across an article from USA Today that stated that individuals whose heart rate drops during exertion are more likely to drop dead of a heart attack. I can't remember the details...I guess I just feel like I should be doing more for this resident. She's had generalized c/o malaise for several weeks, and we have been unsuccessfully trying to find the cause of it. I thought maybe I had found something with the dropping heart rate.

While a HR in the 80s may be considered normal, I say it doesn't hurt to investigate this further. It's definitely better to be overly cautious than the opposite.

papawjohn · Jan 21, 2006

Hey Dawn!!!

I'm an ICU nurse married to a LTC Nurse. I've learned to listen to what she says. (Despite what she might say!!! )

There are really few physiological things that determine the Heart-Rate and Blood Pressure equation. You didn't tell us much about your PT, so I can't make any estimation of what might be actually going on in that particular case. But let me kind of tell you how an ICU nurse would THINK about your question. Sometimes when my wife asks me questions about her PTs this seems helpful.

There is this thing called "cardiac output" which is not too hard to think about, since it is exactly what it says: the am't of blood the heart pumps in one minute.

The 'cardiac output' is the am't of blood with each heart beat multiplied by the pulse/min. (That's pretty self-explanatory, I guess.)

There are a bunch of nervous system hormones and meds that affect the heart rate. (You had to take the Apical Pulse before giving lanoxin when you were in NursgSchool, I bet.)

So I imagine a little nursing home Pt lying in bed and someone takes his BP and HRate. The BP is reasonable and the HeartRate is high-->100. Then the normal meds are delivered at 0900. Some of those meds are digitalis and beta-blockers. The heart rate goes down and the BP goes down--but there is no one to check it at that time. Then Physical Therapy comes along before lunch. They check the BP and HR and find them to be less that before the meds given. So they involve the patient in full PTherapy and then back to chair or bed. Then mid-day comes and lunch is served, vital signs taken. BP and HR (still under the control of meds and with 'resting' and parasympathetic stimulous from full tummy) are down.

So the conscientious nurse notes that the heart rate was high--meds/PT/diet occurred--now the heart rate is down and BP within normal range.

Is that OK?

Well--if in fact that is what's going on, yep--perfectly OK.

Hope this helps.

Keep paying attention to your Patients. It's very important.

Papaw John

dawnb70 · Jan 22, 2006

I'm trying to remember what meds. this pt. is on. She gets Sinemet, Effexor, Mirapex, Requip, Plavix, Diovan, Cardizem, Synthroid, and Lisinopril in the a.m. At lunch she gets the Effexor, Sinemet, Requip, and Mirapex. PT hooks up the pulse ox. while they're working with her (around 10 a.m.), and they reported to me that her pulse was dropping when she was doing her exercises. When she is at rest it shoots up into the 100s again. This pt. keeps begging me to do something for her. She says "I just don't feel good". Yesterday her heart rate was regular with an irregular beat every 4th beat. I reported it to the MD but he didn't order anything new. I asked if we could check her K+ because she has a history of hypo/hyperkalemia. He didn't order anything. We did a BMP last week and everything was WNL so maybe that's why. I've been racking my brain trying to figure out what is wrong with her. The other nurses say she's just attention-seeking or that it's psychosomatic. This pt. prior to her "just not feeling good" was ambulatory, active socially, and very cheerful....now she just lays in her bed most of the time. I'm so sure we're missing something, but I don't know what else there is to check for. HELP!!!!

Dinith88 · Jan 22, 2006

I'm trying to remember what meds. this pt. is on. She gets Sinemet, Effexor, Mirapex, Requip, Plavix, Diovan, Cardizem, Synthroid, and Lisinopril in the a.m. At lunch she gets the Effexor, Sinemet, Requip, and Mirapex. PT hooks up the pulse ox. while they're working with her (around 10 a.m.), and they reported to me that her pulse was dropping when she was doing her exercises. When she is at rest it shoots up into the 100s again. This pt. keeps begging me to do something for her. She says "I just don't feel good". Yesterday her heart rate was regular with an irregular beat every 4th beat. I reported it to the MD but he didn't order anything new. I asked if we could check her K+ because she has a history of hypo/hyperkalemia. He didn't order anything. We did a BMP last week and everything was WNL so maybe that's why. I've been racking my brain trying to figure out what is wrong with her. The other nurses say she's just attention-seeking or that it's psychosomatic. This pt. prior to her "just not feeling good" was ambulatory, active socially, and very cheerful....now she just lays in her bed most of the time. I'm so sure we're missing something, but I don't know what else there is to check for. HELP!!!!

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Cardizem should be your biggest clue. It's typically given to patients to treat irregular rhythms (atrial rhythms....probably atrial fib)and/or slow them down. This med is a calcium channel blocker and will surely slow your rate. Another big clue is that you say she's an irregular rate (a-fib?), is normally 100 or higher (uncontrolled a-fib).

Things seem to be pointing in the 'she has a-fib (or a history of)...and her heart rate slows after receiving her cardizem (which it should)). Even if it remains irregular it's ok, so long as rate improves (drops to 80s).

AS far as her 'not feeling good' perhaps it's not related to her heart rate...??

zacarias, ASN, RN · Jan 23, 2006

I agree, I thought of the Cardizem too at first. As a calcium-channel blocker, it "blunts" sympathetic stimulation. By that I mean that when she exercises, her HR is not as able to "jump up" because of the blocker. However, you said this lady goes down to the 80s when she exercises which is the odd part. Who knows...

papawjohn · Jan 23, 2006

Hey Y'all

I puzzled over this too. Didn't make any sense. Then I thought--'wonder if she' changing her rhythm?' If she went into Atrial Fib during her PT, she'd lose her atrial filling ('kick') and the cardiac output would go down. But the rate would go up--probably way up.

If in fact she was changing rhythm, she's prob'ly going into Atrial Flutter with a regular block. Say, the Atrium is beating 240/min--pretty normal in flutter--and had a 4:1 block, she would have a 'pulse' of 80 on her vital signs.

Maybe it's one of those medical dilemmas where MORE 'blockers' would improve her cardiac output.

Anyhow--is there any way that she could be heart-monitored during her PT session and then again when she is going back to bed and her heart rate 'shoots up into the hundreds'--which of course is not normal or therapeutic either. The 'rebound' tachycardia makes me think that she might have a non-therapeutic Synthroid level.

So those are how I'd recommend you approach her problem. Identify the rhythm and check a thyroid panel.

And congratulations on your concern; she's a lucky lady to have a nurse who's as concerned as you are.

Papaw John

hrtprncss · Jan 23, 2006

Try doing a research on Pre syncopal and vaso vagal effects during exercises. That may point you to the right direction.

dawnb70 · Jan 24, 2006

I was mistaken...She's not on Cardizem. It's Dilt X-R (or Diltacor) I think, which I can't find in my drug book. She has no history of A.Fib, and does not normally have an irregular heart rate. I think I may have found part of the problem though. We recently put her on Risperdal, when Medicaid quit paying for Zyprexa. I think it may have interacted with her Sinemet, and could also be causing the insomnia. According to my drug book Risperdal is a Dopamine antagonist. Plus, it's contraindicated in the elderly with dementia. Now that Med-D has taken over I can get her off of the Risperdal and back on the Zyprexa. I'm hoping this will help. Thanks to everyone for their advice.:)