@predictable , @kanaazpereira
as I already posted in the past 2 years, I had mitralvalve repair (minimal invasive) .they planned a surgical ablation (pulmonal vein isolation) as well. because of my A-Fib's. . I was doing well.Unfortunatedly I had a syncope in the beginning of january this year. I needed a pacemaker. during my stay in the IC after the implantation, a lot of A-Fib's were seen. I I was surprised, as I did not notice any A-Fib's after my heart surgery (4/2016). So I mailed my cardiac surgeon of the cologne heart center and asked for the operation protocol, which he sent me with the information that he did not do the PVI, as the repair of the mitral valve was difficult (anterior leaflet, the posterior is easier).He was afraid to damage my heart by extending the operation and decided to stop. Nobody told me that. I asked him too, if a reverse remodeling in the left atrium might explain the absence of fibrillations, no answer untill now)
during so many months I was happy to live without these fibrillations. fortunatedly my own cardiologist advised me to continue the bloodthinner (Eliquis) in spite of the "absent" Fib's. now I am living with a pacemaker with a warning: AT/AF burden exceeded..you can imagine that I wanted to find out what this means.and posted my question above.. In the meantime I learned that this is quite common, they are silent. 2-3 years ago it became a discussion point among the cardiologists (international). the crucial question is: does every patient with a pacemaker and silent A-Fib's need a bloodthinner? up to now there is no consensus. june 2016 they started a clinical trial in europe, 200 - 250 cardiological departments send their results to the university of münster/germany. .aim of the study is to find out if the constellation (pacemaker and silent A-Fib's) enhances the risk of stroke and the benefit of bloodthinners.
of course I continued my Eliquis . I wonder why nobody wants to know the reason for these silent fibrillations. there must be an explanation. I don't worry about the eventual negative effects of so many beats per minute. but my husband does.

@predictable ,
I forgot to mention an advice my cardiologist gave me. Of course I showed him the answer of the cardiosurgeon from the hospital . he,like me, was quite astonished to read that there was no surgical ablation done. . he thinks that it does not make sense to have a katheter ablation in the near future, as the fib's will come back.
he also said that these silent A-Fib's won't shorten my life expectance. . I hope his opinion will come true.

Thanks, @yoanne. Your cardiologist and mine are on the same wave length: Bottom line, silent a-fibs are good to know and good to highlight on our medical records, but not ordinarily threatening (if our status is stabilized with physical activity, good nutrition, intellectual and emotional enjoyment, and balanced medical therapy).