Yes, my experience saw me in hospital for a night. Sally Norton tells the cautionary tale of enthusiastic diet changers going strictly on to a low oxalate diet phoning her from the hospital emergency room due to symptoms brought on by the oxalate dump that is hypothesised (does anyone have a text book or journal reference for this phenomenon?)
My story is that I have had to be careful with managing micronutrients while in nutritional ketosis. I found I was susceptible to magnesium mineral depletion. So I was supplementing. But not enough, it seems, after 21 day of a plant-free, dairy-inclusive, ovo-carnivore experiment, I had a return of atrial fibrillation (a mild bout, but emergency doctors get excited about a middle age man with chest pains turning up at their door). In the lead up to the heart arrhythmia, I did note increases in crusty eye secretion, finger joint pain, peeling of skin from fingers and hands, and a rapid increase in dental calculus that needed some cleaning.
The heart problem resolved with increasing magnesium citrate dose to 600mg mg per day (based on an estimate of daily ancestral intake [source needed]). I use the citrate salt as it reduces the risk of calcium oxalate kidney stones forming, which is likely during an oxalate dump while on an elimination or low oxalate diet. The combined dose of Mag+citrate in a tablet at that dose is usually way past most peopleās gut tolerance (laxative effect). Whereas it had no effect on me in stimulating a laxative effect. It is another indication that I wasnāt at optimum magnesium levels - a previous emergency doctor advised taking magnesium to āgut toleranceā if I was getting heart palpitations.
So the hypothesis here, after putting the n=1 puzzle together. The return bout of atrial fibrillation was due to magnesium depletion. The Mg depletion was due to a recent diet change (keto-carnivore trial). Based on oral magnesium tolerance (no gut issues with high dose) and clinical history, that the diet change had affected my magnesium status. Then due to oxalate dumping from the low oxalate diet and the now free circulating oxalic acid binding up circulating magnesium creating the electrolyte shift. The other thing may have been the loss of magnesium rich sea vegetables but maintaining calcium rich dairy, and the calcium load out competing any supplemented magnesium for gut absorption.