The scriptwriter colluded with the writer of the article.
One thing that is interesting is that the heart is a muscle so it uses mostly fatty acids for fuel and it could be switching back and forth from glucose from glycogen storage to fatty acids to intramuscular triacylglycerol storage?
But here is the hypothesis, it could be from not increasing your individual carbohydrate threshold, in other words I can tolerate a much higher threshold of carbohydrates then some one just starting out at let’s say 20 grams of carbohydrates; 200 grams of carbohydrates would be equivalent to 20 grams for me because I’m now more metabolically fit than the average Bunny? (I’m going into deeper state of ketosis during sleep? I only sleep every 4 hours so I get a double dose of deep delta REM which triggers HGH twice? And my body is actually utilizing it due to the low sugar diet even at 200 grams of carbs?)
The heart could be requiring more energy than the high fat diet can provide after it builds up a tolerance to it and maybe it needs to switch back and forth more often and why it could throw off the the cardiac rhythm?
 “…At rest and during normal activities, fats contribute 80–90% of our energy; carbohydrates provide 5–18% and protein 2–5%. During exercise there are four major endogenous sources of energy: muscle carbohydrate stores (glycogen), blood sugar, blood fatty acids, and intramuscular triacylglycerols. …” …More
 “…Triacylglycerols, also known as triglycerides, are the simplest lipids formed by fatty acids. It is made up of three fatty acids ester linked to a single glycerol. Most triacylglycerols contain two or three different fatty acids. …” …More