Puzzling Readings on Oximeter

A WORD OF THANKS for all of you long time users of a PM. You are a real help to those of us who are just getting started. You've already answered many questions for me. Keep up the good work. A couple questions (my mother always said I ask too many questions – bear with me.)

I have a Boston Scientific (BS) ALTRUA 60
S606 DDDR for my SSS and LBBB (I'm learning the abbreviations.) BS says that my unit has Ventricular Rate Regulation (VRR) for atrial arrhythmia management
– what does that mean? (I'm basically familiar with the four main parts of the heart and how they work.) I have Paroxysmal Atrial Fibrillation – does this do anything for my A-Fib?

The main question: I use a finger pulse oximeter to keep track of my heart rate. My low rate is set at 70 bpm; however, there are times when my bpm goes as low as 47 bpm on the oximeter as well as a regular wrist bpm check – how can that be when the low rate is set at 70 bpm. I've researched this forum but haven't found the answer – but think it may have something to do with pvcs or A-Fib.

If I'm sitting still in my Lazy Boy, i.e when watching TV my bpm runs a steady 70 bpm. However, when I get up and start moving around my bpm sometimes drops to the high 40s or low 50s. If I continue to walk around the house my bpm “jumps” up to the mid 80s. When I sit down it may drop again to the 40s or 50s until eventually it settles back to 70 bpm. Does anybody have an idea of what is going on? Does this have to do with pvcs – I take sotalol for pvcs.

PKite

8 Comments

pacing

by Tracey_E - 2012-11-16 01:11:34

Many home monitors are not accurate with the pm, either they miss paced beats or the pm interferes and keeps it from being accurate, sometimes they pick up the beats as well as the pacer's pulses so it comes out way too high... when in doubt, do it the old fashioned way with a finger on your wrist or neck.

A finger pulse oximeter theoretically should be fairly accurate and immune to interference from the pm, but it sounds like it's missing paced beats. If you have SSS, it's likely you beat on your own when you are in the Lazy Boy, you get up and your lazy sinus node drops off so the pm kicks in and brings your rate up for you like it's supposed to. Or it could be pvc's, the monitor won't always catch them, but it sounds like your natural rate is what's being counted, not the paced beats.

Do you feel ok?? If you don't feel ok, go get the pm checked and make sure the leads are all where they're supposed to be and it's pacing as it should. But if you feel good, odds are it's the monitor.

Try not to spend your day staring at the monitor! I only count if I feel bad. If the monitor gives me an odd number, I count manually. The rest of the time, I trust it to do its job and forget about it.

VRR, I have av block so this isn't something I would use and don't know much about, but it sounds like a safety feature that kicks in when you are in afib to keep your pulse (ventricular beats) regular when the atria is acting up.

May have a simple answer

by donr - 2012-11-16 01:11:36

P: Your apparently varying HR may be all explained in your last sentence. You have PVC's!

Oximeters & wrist BPM's are notorious for NOT detecting that weak premature beat! Gives you a low HR.

I've lain on an operating table in my foot surgeon's suite & heard their finger oximeter go completely silent when I was having a run of PVC's. I listened to it do the silent thing for the entire period of the minor procedure they were doing on me. Short answer - you cannot trust them as a pulse counter.

I cannot tell from your profile how long you've had your PM, but you ABSOLUTELY MUST learn to trust the little bugger as being reliable & NOT letting your heart miss a beat. It sounds like you are obsessive about your HR. Not good - that will turn you into a cardiac cripple, afraid to do anything from fer that the PM does not function reliably.

Now - that seemingly unfriendly statement leads me to say that building that confidence in your little bionic buddy is NOT easy, psychologically. You have to have some prof for your mind to relax about the subject.

Here's what I suggest you do: Put your oximeter on & sit back in your Lay Boy. Now - learn to take your pulse at the wrist & just do it while sitting there for a while. You have to become proficient enough at it that you can feel the weak premature beats. You do not even have to count the pulse. Just take it long enough that you can match the finger sensing against the output of your oximeter. Eventually you should see that your fingers sense more heart beats than the machine. After you establish that fact, do it enough times that you can safely say to yourself "Self, that oximeter is a piece of unreliable junk!" Then get up, stick it in a distant drawer somewhere & forget about your HR. Your PM will take care of it & you need not worry.

Guess what!!!!! this sort of a concern by the newbie is not at all unusual!

Paroxysmal Atrial Fibrillation - that IS your A-Fib! Paroxysmal means that it comes in sporadic, random episodes of varying lengths. Unless I have misunderstood your question.

Ventricular Rate Regulation (VRR) for atrial arrhythmia management - that means that your PM has the ability to control the rate of your ventricles in response to your A-Fib. IN A-Fib, your Atrial chambers start beating in uncontrolled high rates that MAY NOT be consistently the same. The Ventricles are more massive than the atria & pump more blood at a higher pressure to push it to all the far points of the body. Well, the ventricles just cannot keep up w/ the atria at extremely high rates (a couple hundred BPM) so when the PM senses the A-Fib, it stops pacing the Ventricles at the rate that the atria are following. I'm not sure what rate it does follow for the ventricles, it may be adjustable, but it really does not matter much, because the atria are not being very effective at doing their part. Since there is a one-way valve between the atria & the ventricles, they can function relatively independently of the atria for a short period while they are in A-Fib.

Don



Tracey and Don (2)

by PKite - 2012-11-16 03:11:25

I should have ask, if it is pvcs can the pm be tweaked so as to make be feel more comfortable? Would raising the lower level from 70 to 80 make a change?

Thank you again.

PK

Tracey and Don

by PKite - 2012-11-16 03:11:30

Thank you guys for taking your time and your explanations. It is a great help to us to have knowledgeable people on this forum. I have less respect for the finger oximeter after your comments -- even though the hospitals make a big use of them.

Since I am new to this experience (two months since my implant), I'm not yet at the point of obsessing over HR -- I simply want to understand what is going on. I'm one of those persons who wants to understand why things happen the way they do. If I understand why my bpm seemingly varies I may be able to do something about it (or not).

Whenever my HR seems to go into the 40-50 bpm area, I feel "bad" and have more trouble breathing. When my HR goes to 70+ I begin to feel better and more at ease. Even though my pm doesn't actually go below 70 bpm, something is happening when it appears to that is uncomfortable when it does. Is the uneasy feeling the result of pvcs?

PK

PVC's are the bane of our existence!

by donr - 2012-11-16 05:11:13

PK: Terrible as it sounds, there is nothing you can do about PVC's w/o adding meds to the PM.

OK, so you are so new to the PM that you do not even have a PM download of data yet.

Your PM sits there & monitors everything your heart does. It counts every PVC, whether a single or a run.

One of the problems w/ PVC's is that they are an extremely inefficient way to pump blood. Since they are not a full Ventricle chamber full when the contraction starts, you do not get quite enough blood to feel normal. It will keep you alive, but you will feel like something you step in out in the back yard after the dog has been out. It can be that bad. Make you drowsy, feel like a zombie & go to sleep at the table in Chili's Restaurant & do a face plant in a plate of pasta. (DON'T ask me how I know!) When that happens, you may take your pulse & if not alert to the PVC's, think your HR is about half of the expected 70.

PVC's are probably the worst feeling of the arrhythmias - though I know a lot of people will say that a junctional rhythm is worse (probably correctly, too - if you have one of those, you can get blue lips, be unable to do anything productive & worse).

You have to develop an insight & understanding of the nefarious little beasts to survive w/ them. It sounds like you are having them in BIG bunches - like a 30+% of your beats. THAT, I guarantee you can make you feel exactly like you do.

I've been there, even up to a 50% rate for a while. I hope you have to take my word for it, because I would NOT wish that rate off on any but my worst enemy. You can learn to tolerate up to about a 10% rate of PVC's w/o even noticing them. It takes a significant amount of time, however.

PM cannot be tweaked to help w/ PVC's. The PM can only fix things that are about to happen later than they should happen. It cannot predict the future, so it cannot stop a PVC from occurring. By its very name, a PVC comes early (Prematuire). To get relief, they put you on meds that induce Bradycardia (SLOOOOOOOOW) heart rate, plus some wicked anti-arrhymic drug. Then use your PM to get the HR up to a reasonable level. F'rinstance, in my case, I take Acebutolol (Beta Blocker) to sloooow my heart down & Flecainide to kill the PVC's. That brings my HR down to somewhere in the 50's. Then my PM is set to 75 BPM as a minimnum. Works out OK.

You are in good company - wanting to know what is going on. We will be glad to help you.

BTW: Have you had a PM download (Interrogation) yet? When you have one, be sure to get a copy of the report so you can study it & ask questions.

Don

we hate pvc's

by Tracey_E - 2012-11-16 06:11:29

If you are feeling bad, call and ask to be checked. Make a note of the day and times you had the episodes so they can look it up and see what the pm was doing then.

Usually I just say ditto to don's comments because he's pretty darned smart and he is right that there is usually little they can do about pvc's. But! your pm is new so maybe the settings they sent you home with are causing some of the pvc's in which case they might be able to tweak and fix it. Sometimes adjusting the timing can help if you are pacing ventricle. If you're only pacing atrial, then no, nothing they can do to stop a premature beat in the ventricle. But, if there is ventricular pacing that you don't really need, they might be able to adjust the delay and allow the ventricles more time to beat on their own so you don't have the pacer competing with your own ventricular rate.

I tend to think 80 would feel like you're racing all the time but we're all different. Always ask, can't hurt.

The hospital pulse oximeters probably cost a bit more than the ones we buy at the drug store. And if you think about it, they use it for O2 saturation but still grab our wrist to count our pulse. They don't depend on it either.

Oh duh, just remembered you asked about VVR. Ventricular pacing! It's probably unrelated to pvc's, but ask them to check it out and see if it can be causing it.

Know that it's perfectly normal to take several trips back to tweak the settings to get back to feeling good. They like to make changes in small increments. Any time you don't feel great, tell them! Don't be shy. It won't always be something they can do anything about, sometimes they won't take us seriously and we have to push, but it never pays to keep quiet and suffer.

assumptions

by Tracey_E - 2012-11-16 06:11:39

Call and get checked. We are just assuming it's pvc's, best to make sure.

And I totally get wanting to understand! My dr and St Judes rep are used to me now. They automatically give me the long explanation before I can pepper them with questions. I can accept anything once it's explained to me. I may not like it, but if I understand it I can get over it and move on. Knowledge is power and all that :)

junctional rhythm

by dhusemann - 2012-11-20 03:11:06

Don,
Interesting you mentioned that. about 3 years ago at work I had almost no energy, and was pushing myself. thought it was related to not eating or diabetes.

went to cafeteria and got something to eat and it was very hard to eat. wrapped up the food stood up and felt my chest jump. an emt in our group said I turned white as a ghost and my Lips turned blue as well as my finger tips. and even my hair lost color.

I could hear people around me but I couldn't respond for about 30 mins. Never did find out what it was but what you described fits it to a tee. haven't had it sense but was recently diagnosed with a CFH. My biggest issue when uncontrolled my BP would get as high as 280/200
drh

You know you're wired when...

Your ICD has a better memory than you.

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