band / heart palpatations link?

No disrespect to your surgeon, but what else could the thickening be, but scar tissue???  My band had a "thick circumferential rind of scar tissue" under it.  Most of it was removed, but it wasn't possible to remove all of it.  Nearly all banded folks develop some amount of scar tissue under and around their bands and ports, how much depends on your particular physiology and genetics.