OK I have had an ICD for 3+ years mainly due to an LBB and enlarged left ventricle. Starting about 2 months after keto I got strong twitching on my left side about the bottom of the rib cage when I would lie on my right side. More frequently until yesterday almost constantly. The Medtronic people were able to reprogram it to eliminate it. (I am in the office now)
Turns out that 55 lbs I lost probably included some fat that was insulating the area between my heart and an adjacent nerve. With that gone I got the nerve stimulation when it was supposed to be just doing the heart.
Looks like my only downside other than those dreams about Portuguese egg tarts.