Phrenic Nerve involuntary abdominal spasms

I have had a medtronic biventricular pacemaker for about 20 months and doing fine except for diaphragm spasms when reclining or lying in certain positions. When  I mentioned this at my cardiologist visit, the medtronic tech was able to adjust the setting on my PM and now the spasms are completely gone!

Has anyone else had these symptoms and had their PM adjusted to relieve the phrenic nerve stimulation from their pacemaker?


left bundle 3 wire pacemaker

by lukerbee - 2022-03-24 16:53:27

I am 85, had Boston  Scientific U228 installed 3/14/22 and have frequent, fairly dramatic internal 'slams' mostly lower left, often in synch with heart rate beats.  Felt in lower feft abdomen, back and heart area. Will mention to team on scheduled 3/29 follow up. Chuck 


by AgentX86 - 2022-03-24 18:31:25

I haven't had them but they're not at all uncommon.  There are a lot of these sorts of complaints on then club forums.

The phrenic nerve stimulates the diaphragm, which is where the spasms are coming from (obviously).  The phrenic nerves (right and left) come from the neck and go down the neck, next to the subclavian vein, then down close to the rignt (or left) ventricle.  If the pacer wire gets too close to this nerve it can excite it instant spasms in the diaphragm. 

The solutions are to reduce the pacing voltage so it no longer stimulates the nerve or reroute the lead so it doesn't come close to the nerve.  Obviously, reducing the voltage is simpler, if the heart can capture the pacing signal and have enough of a safety margin. That's likely what the tech did.


Phrenic Nerve Stimulation

by Julros - 2022-03-25 00:55:23

Yes, I had this. The LV wire is quite close to the phrenic nerve and stimulation is not unusual. My jumps and twitches got progressively worse, to the point where my reflux flaired up. The pacer nurse made some changes, but when I was able to see the manufacturers' rep, he was able to dial it in. I have quadripolar leads, and per the rep, this meant there were 16 different options, and he found the right one after about 3 tries. 


by Submariner_07 - 2022-03-27 02:21:25

Yes CRT-D was doing that when I woke up from the implant. The Boston Scientific field clinical rep adjusted the settings for where the signal comes in to avoid a nerve. Or something like that! It went away immediately. 

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