Heart rate low

First post...here goes.
I just had my 2nd icd implanted 3/2/15. I'm 100% VP and never had an issue with slow heart rate before. Twice now in the last 2 weeks my bpm dropped into the 35-40 range for several minutes. Low range on the device is set to 50 so first time went to ER, second time went directly to EP office. Both times they increased the output- 1st time to 3V second to 5V. Leads tested good and EP said no oversensing or other issues with device. Does this sound familiar to anyone?


4 Comments

Threshold

by golden_snitch - 2015-04-21 01:04:07

Sounds like your pacing thresholds (minimum output at which the heart is being stimulated effectively) are rising, so that the programmed output was no longer enough to make your heart beat. Your slow back-up rhythm kicked in then. Could be due to scar tissue around the tip of the lead. Not that uncommon, especially if the lead has been in for many years. Are you paced at 5V all the time now? If so, that'll drain the battery pretty quickly :-( If this is really happening because of scar tissue/high pacing thresholds, only solution is to replace the lead (with or without removal) and place a new one in a different spot.

Is your device being home monitored? If not, that's something I'd ask for, if I were you. Allows your EP to keep an eye on the threshold. Also, many devices today have a so called "automatic capture management" which means that they automatically check the threshold, for instance, every 24 hours, and then adjust the output accordingly. Ask your EP about it, maybe your device has this feature, too, and he can activate it.

Best wishes!

Automatic capture management

by golden_snitch - 2015-04-22 01:04:53

Your new ICD should have "automatic capture management", so that you do not have to program the pacing threshold that high to be on the safe side. If it automatically monitors thresholds, it can adjust the output as needed. I usually only need an output of 2.0V for my ventricular lead, but there are days when I need 3.0V, and then my pacemaker adjusts to that, so that I do not need to run around with 3.0V all the time. Ask your EP about it!

Auto capture

by Wolf - 2015-04-22 09:04:13

Thanks again for the response. When I spoke to my EP he said that it was set up with the auto capture before but they turned it off at the moment. Still having the low heart rate today, although it was a bit higher today- in the mid 40's off and on. Hopping to get an answer soon, the EP seems almost convinced that adding another lead is the right call, but wants to see if they need to replace the other ventricle lead.

Re:threshold

by Wolf - 2015-04-22 12:04:14

Yes. It's is 100% paced at 5V since Monday. When the EP adjusted it to 3V 2 weeks ago the updated battery life dropped from 10yrs to 8yrs. I'm sure it'll drop more at 5V. Pacing threshold at the EP office was only .5V but the EP and the guy from Medtronic were concerned that there still could be threshold issues so they increased to be safe and will monitor. I am set up with the home monitor (Carelink). Got a call back from the both my EP's today (yes, I now have 2, long story)- they want to do a MCART for 2 weeks to see if it detects any issues, they also mentioned possibly adding a second lead to the ventricle.
Just not happy. Had my 1st ICD for almost 8ys and didn't have this issue. Had many others issues just not this...guess we just gotta work out the bugs. Still not to thrilled but not really another option at this point. :-)

Thanks for the response

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