Dear Sir Thanks for writing to us. An unexplained bruise could have been due to a cardiac thump or an attempted defibrillation in such circumstances. At times high heart rates are associated with such dangerous cardiac rhythms that their reversion is mandatory in initial few minutes. When a defibrillator is not available, the next possible thing is a thump reversion. Someone might have tried it when she fainted. Other possibility is that she may have been given some blood thinners in the hospital which has caused the bruise. These are given in patients with acute cardiac conditions. Sincerely Sukhvinder