Colleen passed out yesterday! She scared me to death. I was about to put her in her crate and something was a miss. She all of a sudden took about 9 short gasping breaths and then fell over, legs in the air. I had no idea what to do. I calmed her and she was still alert. I called the emergency vet and rushed her over. She had just been there on Monday for her check-up and nothing was found. They checked her chest x-rays, ecg, blood and ultrasound against the ones she had 3 months ago and nothing has changed. No fluid build up anywhere. She still has a leak in one of her mitro valves, which i knew. but it remains unchanged. So now she is wearing a heart monitor for 24 hours. I don't know what to do, i am hoping it was just a freak thing. Has anyone else had this happen?? She is a normal healthy dog, accept for the heart which we are monitoring.