Upper Body Conditioning with ICD

I found out the hard way that I shouldn't have been doing push ups.  Was defibrillated 10 times one morning while running.  The doctor determined it was my weight lifting and push ups, not the running that caused clavicular pinch.  Two doctors told me to never to upper body exercises even though the re-implanted using the cervical vein rather than the sub-clavian artery.  Would it be OK to do isometric exercises that don't involve repetitions?  I'm am wondering about holding the push up position for increasing lengths of time, for instance.  Any other suggestions for keeping muscle tone in the upper body?

[Cleveland Clinic]

We almost never have to worry about most of out pt exercise routine because most of them don't exercise to that degree.  I am not sure what to tell you at this point. I would certainly avoid doing push-ups.  As far as the isometric exercise, I think that woud be safe given that there really isn't any tension put on the leads.  I would confirm this with the electrophysiologist who implanted the original device, or get a second opinion.  Sorry I can't be more helpful.  I will check with others to see what they think about this.

[n2rnn]

Thanks for the response.  I have had several doctors shake their heads when they look at my records.  They just throw up their hands and say "We just don't have much experience with healthy people wearing pacemakers! Most of our people are barely moving and here you are wishing you could run a marathon!"  I'm trying to trim my sails and be a more "normal" 63 year old.
Mark n2rnn

[n2rnn]

In my original post, that should read "Cephalic Vein,"  Big difference!
Mark n2rnn