I was aware that pulmonary veins were the source of many ectopic
events, but not how the left side made it worse.. Your mention of
traction was a big help. It led me to finding out about stretch
receptors and their role in the mechanics of this process. Stretch
seems to produce multiple electromechanical effects, though, so the
exact mechanisms are still a bit unclear to me. Given the variety of
effects, it might be that different effects are more or less important
in different people. And, it is not that clear to me how this trigger
can produce sustained afib unless the afib produces significant
changes by itself. It seems to be related to feedback effects in afib,
and I'm trying to understand that better.

The physiology gets a bit involved too. I am not clear if the real
problem is associated primarily with myocardial extensions around PV's
or if there still can be significant ectopic sources in normal,
non-extended or non-dilated PV's.

In any case, I now have a much better understanding of what happens
mechanically. It is quite complex, though, so I have much more to
learn.

And I'd like to thank you after the fact too. Your description was
quite helpful.

As a devout person, I'm sure your Christmas was very happy and filled
with joy, as was mine. I wish you a happy New Year also.

Tom

Clearly you remain convicted by the Holy Spirit:

http://HeartMDPhD.com/Convicts