Why does my heart race like crazy right before a bowel movement?

[Izzy87rios]

Hey! I need your help guys!! my name is Izzy and I've been getting these strange episodes for about 10yrs and doctors can't tell me what they are or what's causing them. When I get an episode I get sweaty, hot, sometimes dizzy or nauseous and ether my heart races above 100bpm or my blood pressure goes up I've even had the instance where my heart rate gets low in the 50's. When all this happens I always have to take a bowel movement and all the symptoms won't subside until I do. My stomach is usually gargling when this is about to happen. I was also diagnosed with Crohn's disease about 4 years ago and I can tell when my stomach is more upset i get more of these episodes. They can last anywhere from 10-30min. They are terrifying, I've had my heart rate go over 160 and it feels like I'm going to pass out. I'm on a beta blocker for sinus Tachycardia but it doesn't help when I'm having theses episodes. Could it be my vagus nerve that's causing all of this? Any feed back would be great.. I also get dizzy like I'm about to black out when I suddenly stand, it's not related to my
Episodes thought it just happens randomly throughout the day. Another things I don't eat unhealthy just eggs, bananas, avocado and chicken. Those are the foods I can tolerate because of my Crohn's I only weight 102.