How fast does an icd not pacing fire? Is my bpm reall4y messed up or my polar going bad?

[Pamz]

After my icd fired 6 times 2 days ago at 170, I should be safe at the new 210 setting but, to be sure, I'm wearing my polar monitor all day.  Mowed yesterday afternoon and maintained 130 and below but then took the dog for a really slow walk and went from 110 to 200 & back to 114 after sitting down for a few seconds.  Today, drove home from town 25 miles and then carried 3 bags in to the house and before I even got to the door, I was beeping and looked down, it was 210.  I laid down immediately and it stopped withing 5-10 seconds, dropped down to 145.  The icd didn't fire on me, which is great but now I'm confused.  How fast do they fire?  I don't know how fast it was the other day - I didn't have my monitor on.  It's always done this to a point but I wasn't worried about it before the icd, now I'm not sure what to think.  About a week ago, my bpm showed 178 several times in a row while I was jogging, I'd stop and my bpm would drop.  I was thinking monitor not working but then, it showed up on my icd reading, so the monitor was right.  But, is it working now?

[Pamz]

The long and short of it - that's funny!  The ambulance drivers didn't say anything about my t waves but they did say that I had a strange R wave, real low or faint and I have read that can cause problems.  The reset is working out ok though, been out jogging and working, including mowing and been ok.  

[stevie_wonder]

Hi Pamz,
I just read your profile (probably should have done that before I posted before!) and it says you have Short QT Syndrome. Well I have Long QT Syndrome. Together we make up the "Long and Short" of it... lol

I have done a lot of research on LQTS and ICDs and have come across some info on SQTS and ICDs as well. It seems that ICDs can double count the T waves more often with SQTS and this could be what is happening. So it really is important to keep that heart rate down to avoid this from happening. Ask your EP if this is what caused your 6 shocks and have him explain it to you. Some people with certain LQTS genes can have this happen as well, luckily for me my t waves are very small and don't confuse the ICD.

Take care,
Diane

[Pamz]

Thank goodness, don't think I have any issues like that happening.  My pacemaker won't let me get below 60 now - on my own I could drop to 30 but, I was so used to it, never made me pass out - I felt normal.  Hope all's under control now.

[Pamz]

You made a lot of sense and now I really wonder what my settings are.  They just told me 210, no matter what I'm doing.  I don't see the EP again until late September or I set the defibrillator off again, which I doubt will happen.  My poor son is thinking he can't jog cause he's hitting heart rates of 180 very quickly and he's afraid that it's going to fire on him.  I told him Mayo said not to let him over 207 so I think he's good to, there.  But, I wonder.  We do need to talk to them and get a lot of answers.  Of course, he's getting afib issues I guess, even though he's only 25.  I told him to switch over to my cardiologist and see what they can do so he's looking in to this.  This is something, and, now my daughter has tested with this genetic defect also and she's not going to deal well at all.

Thanks for the info.

[stevie_wonder]

Hi Pamz,
So sorry to hear that your ICD shocked you. ICDs are programmed to shock you if they detect ventricular tachycardia (VT) or ventricular fibrillation (VF). This means that your heart beat is originating from the ventricles in the bottom of the heart and not the atrium at the top part of the heart which is where the heart beat is supposed to originate from.

If your ICD detects VT or VF in your heart rate zone that is programmed by the doctor it will shock you within 7-9 seconds in most cases. But this all depends on how the doctor programmed the detection zone. For instance, my ICD is set to shock me if it detects VT or VF at a heart rate of 200 bpm and if 18 of the last 24 beats are ventricular in origin and not atrial.

The ICD constantly counts beats both atrial and ventricular. PVCs are counted and if there are 18 in a row my ICD would shock me. Is this making any sense? There is a lot more involved than just heart rate when it comes to ICDs shocking us.

At your next appointment make your EP explain it to you so that you don't live in fear when your heart rate reaches 210. Because if your heart rate is 210 but is coming from the atrium the ICD should not shock you regardless of heart rate. Unfortunately ICDs not only shock us appropriately when we need them, but they can shock us innapropriately when they think they detect VT or VF but it is really not. 20% of ICD patients receive innapropriate shocks in the first 18 months. Newer ICDs and newer programming methods are reducing that number but any shock is one shock too many!!

It really angers me that doctors don't explain all this to us before hand. I was fortunate enough to have a very good EP that explained all the benefits and disadvantages of ICDs.

I hope I made sense in my rambling and that you don't ever get shocked again.

Take care,

[Mom2four85]

yes sometimes when my HR goes high out of control the PM has to pace me back down I pass out - it's due to a sudden decrease in my HR or bp - but that's due to ANS problems and my whacko system - sending mixed signals; I've passed out with a HR in the 50's which they say shouldn't happen

the reason I asked about rate response is that was part of the problem with mine - when I would exercise, my PM worked against me and would see my higher HR as being dangerous and would pace my rate back down where my heart wouldn't work on it's on - I went almost a year and none of the techs or dr's checked this; I found out when I switched to a new cardiologist - that's the first thing they checked when I told them my symptoms; something you may want to mention to whoever checks your device

[Pamz]

Same, all one unit, pacemaker for bradycardia and defibrillator for arrymthia's - think it's short qt syndrome but the gene mutation is unknown and I barely show short qt - my son and brother suffered sudden death - my son survived, my brother didn't.  Heart rate stays low too long while exercising and then it attemps to catch up & goes overboard.  Yesterday, Dr downloaded my device and my heart rate was lower than the hrm's, so, both were not working well.  They tested one monitor and it was slow following.  The new one was just whacked.  Defibrillator is now set at 210 and it will fire within 10-15 seconds, no pacing.  Don't kow about rate response.    

Pacing makes you pass out?  Mine paced on Sunday at 178 for 3 minutes, didn't phase me at all.  I was in full movement when it knocked me down.  Was walking slowly on the 3rd hit, running on the 5th hit.

Got a new polar chest strap and mowed tonight pretty fast paced and never went over 115 so, that's probably right.

Hope all goes well with you and thanks for your response.

[Mom2four85]

Did you tell your doctor what was going on so they could look at your ICD and see if the rates are the same as your monitors? That's what I did, like you my rates for my icd were way too low and they reset it for 210 like you - I have 15 sec then it's bam I hit the floor

another thing - my rate response was off - means my heart can't take over when it's supposed to and my PM will pace me back down during exercise or exertion which caused me to pass out.

I'm curious about something above; I read you got an icd for bradycardia? I got a pacemaker for my bradycardia and an icd for malignant heart arrythmia's that caused sudden cardiac death.  Maybe I read it wrong?

[Pamz]

Thanks to everyone - it is 15-20 secs - called the cardio & asked.  Bought a new monitor today - what a disaster.  Set it, put it on took off down 3 flights of stairs & jogged 1 block to the car.  Got 1 block away and monitor's beeping-229.  Stopped & it dropped in secs.  6 blocks to my parents took 1/2 hr because of all the stopping (should take 6 min).  Then I realized I bought a dual, chest strap shows continuous read & 2 fingers pressed on watch gives an instant demand reading and the instant demand reading was normal between 60 & 145 & I believed the demand reading so, anxiety over and drove 20 miles home.  Put old & new monitors on together with old strap & went for a jog, old one up to 197bpm almost instantly & then 0, new one on demand only 114 & then it began working with the chest strap also, around 114 reading.  When walking, all 3 readings at 60, which is what the pacer is set at.  What a fiasco.  New one's going back (don't like the car), old one getting turned in for warranty and ordering a new one in the morning.  

But, I'm happy, got a short jog in between the 2 monitors & heading for the treadmill now.

[kevk]

I have to have a high rate for at least 15-20 seconds before my ICD will fire.

[itdood]

Need to ask the doc, I believe they can set them for how long the rate is at a certain level.  It could be set that:

If rate >/= 210 for longer than 10 seconds then fire

[Pamz]

My polar said bpm of 210 but my icd didn't fire even though it's set at 210.  The polar said I dropped my bpm within seconds so I was wondering, how much time I have to get my bpm to drop or, once the icd starts ramping up, is there nothing stopping it?  I want to rely on my polar to know where my heart rate is at but I just can't tell if it's working correctly.  I think I'm going to get a new one, this one is about a year old so my battery life may be coming to an end.

My heart rate has always bounced around since I've been monitoring it.  Extreme highs and extreme lows and I don't feel any different one way or the other.  Some days I run the stairs to my office, my bpm hits a whole 70 (3 flights) and then the next day it'll hit 170.  My son's and daughter's bpm's are both the same.  Don't know what it did before my son's scd because I never thought about it.  I'm fit and plan on staying that way, don't like tv and don't like to sit, love to be outside working.

[debbier]

Hi Pam,  I have read your last two posts and I was wondering if you have  always had issues with your heart rate getting elevated so quickly or is this new since your ICD?  I read you had brachycardia an that caused the ICD.   I would think your heart is still recovering from the procedure so you may have issues until they get your settings correct.  You are an inspiration to alot of people,  you are living your life and not letting this issue make you a couch potato.  I hope everything calms down and your able to get on with your physical activity without any issues.

[Jerry_NJ]

I don't follow your story completely, but if I've got it right I'd not worry about a device being set at 210 and another saying 210 and the first one didn't "fire".  I'd guess the ICD is seeing the real bpm... the polar may be subject to some interference/noise/juggle/whatever.

Sounds like you are very active physically, good for you, not letting the heart rule your life.  It is good you wear a monitor and keep you HR below a reasonable number, e.g., 160, or 150...