Biotronik Evia and 2:1 Heart Block – Pacemakers Explained

Readers Questions!

“Hi , I’ve posted this on the pacemaker forum but would appreciate your insights. I received a Biotronik Evia in May for intermittent complete block (23 pauses in as many hrs on the Holter). Rate response is turned off and night mode set at 45. I believe the hr is set at 50-130, although I could be wrong. At the 4 week check the tech said the ventricular lead hadn’t fired, which he thought was odd for my condition. It was also firing too high when he checked, so sent me for an X-ray to check position of leads.

Cardio was happy with X-ray and checked home monitoring data and was happy – wasn’t concerned that v lead hadn’t fired – battery will last longer!
At follow-up 4 weeks later ventricular lead still had not fired. Cardio said it wouldn’t because my heart hadn’t slowed.
Odd because both he and the referring cardio were at pains to explain that the pauses were caused by faulty wiring, which to me means that hr would have no effect on whether the signals were getting through the av node. Unless the more there are the more chance of them getting through.
Anyway would appreciate any insights you might have as I think it unlikely that I was just having a bad day when I had the Holter. Incidentally a diff cardio wanted to implant a pm 7 years ago after 11 pauses, one of 4.3 secs. I thought he was being overly cautious but obviously I have had a problem for a while.”

For obvious reasons I cannot answer your question directly as I do not know all the ins and outs of your case.
From what I can ascertain, at your 4 week follow up your ventricular pacing was 0% and your Ventricular Threshold was probably up a little from when the device was implanted. So your technician and Cardiologist did the right thing in ordering the x-ray as they wanted to ascertain that your lead hadn’t moved! Off of the back of this x-ray they were obviously happy that everything was as it should be.

The tests the technician would have run must have convinced them that the pacemaker was sensing (seeing what the ventricles were doing) correctly and also pacing (kicking in if the need arrived) correctly. 

A big question is whether or not you are having symptoms associated with pauses? Let your doctor/technician know if you are! If you are still concerned maybe ask for a 24 holter monitor.

About the EVIA and CHB
Intermittent complete heart block means that every now and again the signal from the top of your heart (Atrium) aren’t reaching the bottom of your heart (Ventricles). This doesn’t have to occur very often! I once had a patient who had 8 seconds of CHB in 3 years! So it can happen.
With the Evia pacemaker I believe (am pretty sure) has the ADI=DDD algorithm VP Suppression (Copywrite Biotronik) is used. This only allows one blocked Atrial event without mode switching, if there are two blocked atrial events then this will switch to DDD and the ventricle will be pace.
If a dual chamber pacemaker could be and was set in an AAI only mode this would only concentrate on what the top of the heart was doing and wouldn’t pace in the ventricles, in someone with Intermittent Complete Heart Block you would never use this programming.

Remember I am simply speculating as I do not know the ins and outs of your situation, if you have any concerns always discuss them with your doctor/cardiologist/technician. In NO WAY is this a medical advice. If you have any questions or concerns regarding your own health these should be discussed with a qualified health practitioner/doctor or your own Pacemaker technician. No information should be used from this website to alter your lifestyle, adjust your treatments or as a tool to contest your health care professional. We are all individual and each case needs to be taken on its merits I am simply explaining some concepts involved in the wonderful world of Cardiology.

Cardiac Technician 
Time to go to work.

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