Drop in EF after pacemaker replacement?

After 8 years of a functioning Boston Scientific N161 CRT-D, which had significantly improved my heart function, it was necessary to replace it.

New device: G151 CRT-D.  

Just prior to replacement, my EF was 65. Shortly after replacement my EF was 48, with symptoms of fatigue and shortness of breath.

My electrophysiologist even agreed that seemed more than coincidence; however, he could not find anything wrong with the new device or its leads.

Anyone have siminlar experiences? 

Really frustrated because it has really affected my quality of life.




by Vii - 2022-07-08 02:21:42


I don't have a similar experience, but hearing your case is quite concerning to me.

Did you notice the shortness of breathe the same day you got the replacement? If so, maybe something happened during surgery.

It seems like your device is a ICD that has pacemaker abilities? Did they shock you during surgery to test the device? From my understanding, shocking you can cause your heart to be damaged. May take some time for it to heal...

Maybe somebody with a ICD can provide some feedback on  how shocking affects the heart.

Hopefully nothing serious

by Gemita - 2022-07-08 06:05:41

PETeacher, hopefully this is only a short term problem and a pacing adjustment will help alleviate your symptoms and improve your EF.  I see you have a history of VT (ventricular tachycardia) and PVCs (premature ventricular contractions).  Are these under firm control?  Arrhythmias and any health condition present, even medication and lifestyle changes may affect EF but hopefully your fall is only a temporary one and at your next echo check your EF will stabilise.  Although a fall from 65% to 48% is concerning, 48% is only just below the normal range (50-70%) for EF.

Your symptoms of fatigue and shortness of breath are more concerning though, especially if you were free from symptoms before your replacement pacemaker.  Have you ever experienced these symptoms before or had a very low ejection fraction due heart failure?  I see you have a CRT pacemaker with defibrillator.  

Another question.  Have you been given the same settings as your previous device?  

I get fatigue and shortness of breath with VT (non sustained) and PVCs.  I would perhaps ask for some extra holter monitoring to see what might be causing your symptoms and for treadmill testing to see whether your new device settings can be fine tuned to suit you better.  

Drop in EF after pacemaker replacement?

by PEteacher - 2022-07-09 09:28:54

Thanks for the feedback.  The original pacemaker implant in 2009 for complete heart block.  In 2012 upgraded to CRT-D due to an episode of VT and diagnosis of cardiac sarcoidosis.  My EF went from 37% up into the 50's - 60's.  Things have been good until this new pacemaker implant due to battery expiration.

I have total confidence in my cardiologist and EP, but sometimes even good docs, need some prodding to look more deeply into things.  I know this from experience after going 4 years with obvious declining heart function, prior to sarcoid diagnosis.

Sarcoid disease progression?

by Gemita - 2022-07-09 09:48:57

Thank you for the update. I am so sorry to hear about your Sarcoid disease PEteacher.  Hopefully your cardiologist and EP will get to the bottom of your sudden fall in EF following your battery replacement and will be able to bring your EF back up very quickly.  I do wish you all the very best

Re: Drop in EF

by PEteacher - 2022-07-10 01:47:51

Thank you Gemita :-)

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