Keep getting "thumps" in my chest

Well- I received my ICD on June 2nd so I guess I am now 3 wks post implant (seems much longer). Ever since then I have these "thump" feelings in my left/middle chest behind my sternum. Like someone tapped me with one of those rubber reflex hammers- not painful but very noticable. There are usually 2 or 3 right in a row. I don't have them every day but sometimes it is several days in a row. I had them Sat, then Monday & Tues this week.

I never had any documented arrythmia and they implanted the ICD as a preventive measure due to my LVNC. They did think it was possible that I had arrythmia in the past though when I described many sleepless nights in which my heart felt as if it was "racing" but nothing was ever documented.

One person I asked mentioned PVC's but this is completely new. I would remember if this had happened before. Another mentioned compressed nerve endings and just the device settling.

I did call the Dr and basically twisted their arm into making an appt for me on the 30th. I would just like to hear what my wonderful PM club friends might think. Questions I should ask?

I don't know if that is what a shock is like- I was imagining that a shock would be a single time not multiples??
Could it be the pace function?
Thanks in advance!



by HelenB - 2008-06-24 04:06:12

Hi Candi,

I am almost as new to this as you are so I am sure someone else can answer your question much better than me.

I just wanted to tell you that for a while after my implant I had muscle spasms in the area over the ICD. It felt sort of like you describe, and when you looked at my chest you could actually see it "jump". I was freaked out at first, but luckily I was still in the hospital when it started so I had the doctor watch it happen. They said it was just muscle spasming and it was my body's response to pain.

Anyway that could be one suggestion but of course I'm sure there are others! Hopefully you'll get some answers when you see the doctor.

Take care,


by scadnama - 2008-06-24 04:06:13


I also have the thumping feeling in the exact place that you describe in my chest. I felt it very often when my pacemaker was first implanted, but now I only feel it occassionaly. I called the Medtronic rep at my Dr.'s office, and he said that I was probably feeling the pacemaker working.
When I went in for my first check-up and the magnet that communicates with the device was placed over my chest, I had the exact same sensations. So, it was in fact my pacemaker working that I felt.
I am paced at about 70%, but I only feel those thumps once a week or even less, and they become less noticable as time has gone by. I have had my pacemaker for 7 months now, and those thumps now reassure me that my little buddy is doing it's job!

Take care,


by candi51 - 2008-06-24 06:06:04

Thanks for the input so far!

My device is an ICD and I was under the impression that it only paced after a shock until my heart regained it's own rythym. So that being the case I don't think I have all the feature of a PM like rate response- but I could be wrong. I do know my device is the "basic"- only one lead.

The "thumping" feeling is deep inside and I can't see it but boy does it stop me in my tracks.


by BOB 1 - 2008-06-24 06:06:15


If you have a pacemaker that has a rate response feature that is activated, that could be where your thumps are coming from. At least it was for me and a few others I have seen commenting here for the last year or so.

In my case when the rate response was speeding up my heart rate due to increased physical activity its timing was ever so slightly off and it was causing the ventricle to contract a millisecond or two before the atrial finished its work of pushing blood through the mitral valve into the ventricle. The early ventricle contraction caused the mitral valve to have pressure being applied from both sides and was that causing my pain.

The PM timing was not off enough to cause a problem with the overall function of my heart, but it was enough to get my attention every time it happened. After several tries at getting the timing correct and failing I asked to have the rate response turned off.

The only difference I notice without it being on is I know longer have the pain in the center of my chest.


rate response and pacing

by HelenB - 2008-06-24 06:06:22

Hi again Candi,

I've got an ICD too. I believe that many of the new ICD models do have a rate response feature. My understanding is that this allows the ICD to know when your heart rate is elevated due to exercise or when you are actually starting to have a bout of tachycardia. (that could be wrong though..!)

The newer ICD's can also pace you to some extent. Mine will pace in an attempt to stop tachycardia before actually delivering a shock. If it can't stop it by pacing, then it will deliver cardioversion, and if that doesn't work, then defibrillation. I think I have felt it pace me before, but it didn't feel like a thump... more like gentle pulses. Certainly nothing to stop me in my tracks as you have experienced.

You'll have to let us know what the dr. tells you on the 30th, or maybe someone else on this forum has some suggestions.

Take care,


by BOB 1 - 2008-06-24 07:06:53


My mistake. I doubt that you have a unit that has a rate response feature if it has only one lead. It is my understanding you must have at least two leads as impulses must be going to the atrial and ventricle for rate response to work. And I could be dead wrong about that too.

I see people here using ICD (Implantable cardioverter defibrillator) when referring to both pacemaker or D-Fib unit. Since your symptoms sounded so much like those I had, I thought you probably had an ICD/pacemaker combination. But it is not likely to be that with just one lead. Yours must be a D-Fib unit whose only purpose is to stop a runaway heart beat with a jolt or two of electricity.

So I have no idea what is causing your thumping. I sometimes see people saying those of us with pacemakers are like the Energizer Bunny. Sounds like that could apply to you in more ways than one.




by HelenB - 2008-06-24 09:06:53

Hi Candi and Bob,

I have a defibrillator only, to clarify - and it's 1 lead as well. I thought it had a rate-response function only from reading the literature given to me, not from being told that, so I could be wrong.

I think, from what my doctors have said, that the "pacing" I was referring to is the gentle electrical pulsing given out by the lead when it first senses a dangerous rhythm. It tries that first, then cardioversion, then defibrillation. It's not the same as what a pacemaker does, though they still called it pacing when they were talking to me.

Anyway... I am still learning a lot about this myself so I could be completely wrong. Bob... you sound like you understand these things pretty well. Am I getting it? :)

Thanks! Hope you are feeling better Candi,



by candi51 - 2008-06-24 11:06:03

Got the 1st bill today- $96,000 not including all the Dr fees!
My device alone was $56,000


by candi51 - 2008-06-24 11:06:04

Thank you Helen & Bob for trying to help me figure this out.
It is true that ICD and PM's are so different and every single person's case is so different. It is fascinating to me!

We were also confused when they first started talking about the ICD and then said it had a pace function. I know at this time I have 1 lead but they can add up to 3 more if my heart diminishes more.

My husband remembered that the rep in the hospital set my high rate at 220 and the low at 40.

In the 1st appt I had with the EP I asked about the difference between PM & ICD and he said that the ICD's he uses were both. I have in my notes where the Dr said that it shouldn't pace unless my heartrate got below 40 because that sometimes happens after a shock.

This is all very confusing and I am so thankful to have you all to help sort it out.

This definately helps with questions to ask the Dr.

I have a friend that is a St jude rep and I will see if he can help shed some light on the differences too.

Defib Units

by BOB 1 - 2008-06-24 11:06:12


I think you are getting it at least as well and probably better than many of us.

For what it is worth, I agree with what you say about your defib unit triing to do. In fact, I think I have read some where that the newer units do that in an attempt to stave off a full blown defib attack.



by HelenB - 2008-06-25 09:06:38

Thanks Bob!

Good to know I am starting to figure it out - there is a lot to learn! The technology is really fascinating.

I don't think mine has a PM function... not sure, though. I'll ask when I go in. My heart rate is usually very high on its own.

As for price... these things sure are expensive! I think my device was around $40,000 Canadian... we're walking around with treasure in our chests! :)


by Red1958 - 2008-06-28 08:06:45

Got my 3-wire CRT--D 1-21-08 and every time i exhaled and held my breath i got this big thump under my left ribcage.In march had my first defib adjustment.Been thump free since.

thump thump thump

by Daffy - 2010-12-26 02:12:33

I don't have an icd just a crt p.. three leads. Ventricular leads are to help asynchrony of the ventricles due to LBBB. Atrial lead for bradycardia. Had it inserted 3 days ago, and I continue to feel the thump thump thump below my left breast.. like at the bottom of the heart. I called the dr's office, but of course, Christmas happened. They told me to wait until Monday and call back. This thump is not continuous, but almost so. I have a few seconds without it and then it starts again. Very annoying. Rep at hospital said I was pacing at 89%. Sure hope that Monday they can do something so I am thump free but with the gadget still working! Must go to bed. I keep falling asleep at the computer or whereever I am. Is that typical 3 days post pm?

2 1/2 yrs later

by candi51 - 2010-12-26 11:12:13

So after 2 1/2 yrs I still have the thumps several times a day. My new doc is increasing the beta blockers thinking it is an arrythmia but they haven't ever done a holter monitor and he said it doesn't matter what the arrythmia is since I have the ICD....Don't know that I agree with that but am sticking with it for now.

Daffy- It almost sounds like you are just feeling the pacing from your device. I know I can sure feel it when they are interrogating my device and I know for a fact now that I am not paced at all except for when they are doing checks.
I know lots of people who talked about feeling the pacing at first and then got used to it. It is the best plan to discuss it with the doc and see what they say. I know PM's have so many boggles my mind!
Good Luck

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