Died after bloat surgery.

My dog became sick early Friday morning (2am) and vomited 3 times between 2am and 6am. She was extremely thirsty and would not eat in the morning (fed twice a day). I noticed her abdoment was enlarged and called her vet, they saw her right away. her vital signs were all normal, she was active and alert, but xrays showed that her stomach was extremely bloated and twisted. She had immediate surgery to untwist and empty the stomach, and we also opted to have her stomach tacked to prevent this from happening in the future. I was called about 1 1/2 hours later and they said the surgery went well and that the stomach and spleen tissue was pink and healthy, indicating this was caught early. I received a second call about 10 minutes later saying that Roxie had gone into cardiac arrest and they were unable to revive her. The explanation was that sometimes when the stomach gasses are released they overwhelm the dog's electrolyte balance resulting in compromised heart function. She was given lidocaine throughout surgery and had some heart arrhythmia early in the sugery, but it had been resolved.

My question is: Is this outcome often seen in young, healthy dogs where stomach bloat is caught and treated early or did she maybe have a pre-existing heart condition that caused this?

Thanks so much for your reply and kind thoughts. It has been a very painful experience.