What Causes Hot Flashes In A Heart Patient?

On 4-5-2015 I passed out in church. I have never done this before. Three and one half years ago, I had valve surgery repair to the mitral and aortic valves. I have been pretty much ok except for an occasional afib episode. Occasionally I will get the irregular heart beat and correct it by bending over and coughing a few times and then all is good for a while. On 4-5-2015, nothing was different that I could tell previous to passing out except that in church, I was getting hot. I took off my coat(still feeling too hot), was standing up for a few minutes then we sat down and in about 5 seconds, I was gone. I woke up 3 to 5 minutes later, an off duty policeman had removed my sweater, unbuttoned my shirt and tie, and my legs were up on the bench so I was lying down. I was told that I had no pulse for a while. They called the ambulance and they took me to the local hospital. I also had urinated on myself. In the ambulance, they checked my blood sugar to be too low, and they gave me something with vanilla in it to get my sugar back up there. In a few seconds, they checked the level again and it seemed to go lower. At the hospital they said I probably was dehydrated and that I was experiencing afib at the present when they hooked me up to an ekg machine They admitted me and did tests such as checking the corroded arteries in the neck-checked OK. They also did an ultrasound of the heart to be ok also. The afib went away after about one and a half hours in the hospital. The doctors called in my cardiologist and she said I could have been dehydrated, they put me on Lopressor and eliquis and put me on a heart monitor for 30 days. In the 30 days, I did feel some palpatations but they pretty much stopped coming after about 2 weeks. I still am on the eliquis and Lopressor and am drinking as much as possible such as water and an occasional decaf coffee. I cannot imagine that I was dehydrated so much as to cause me to pass out and also being extremely hot before passing out. My routine was no different that day than any previous days. Today as all days I have a bowl of fiber 1, skim milk with a banana or raisins. After this I have a peanut butter sandwich in between 3 slices of soft rye bread or whole wheat bread. I had a stress test about May 16, and all results seemed fine and no afib. The cardiologist said the hot flash , that I had may never come back. He also said to keep taking the eliquis and Lopressor and keep staying hydrated by drinking water. Any other thoughts. Peter Battistoni YYYY@YYYY