Not a medical man myself, but Dr Google has this https://www.ahajournals.org/doi/10.1161/JAHA.114.001599
The DKA may have been affecting your kidneys as well as stressing your heart. As a layman, I would venture that the DKA came first due to insulin deficiency, leading to a general shutdown reaction to DKA. The stage after DKA happens to be diabetic coma, so maybe this was a close encounter and a severe DKA. Unlikely to be the other way round. The IV drip may have been insulin, but also may be bicarbonate as a treatment for the heart. Just guessing here since I have not experienced anything like this myself.