Dear Sir/ Madam Thanks for your query to us. I am afraid we will not be able to help much on this issue, as it involves so many speculations. First of all it is important ot know what was rhythm when the heart stopped ? If it was a complete cessation of electrical activity or it was Very high abnormal rate? Anything from electrolyte imbalance, cardiac ischemia, anesthetic drugs, handling of certain abdominal organs by surgeon, irritation of peritoneum or previous cardiac disease may be responsible. None from outside can pinpoint. only those who saw the events diligently will be able to throw light, unless there is something very forthcoming. Hope it gives some insight. Sincerely