Have Asthma, Low Pulse Rate, Lightheadedness, Dizziness. Taken Advair And Done EKG. What Do We Expect?

I'm 50, do karate twice a week. I have asthma and take Advair 500/50 twice a day and have been since shortly after Advair came out. A month ago I was in a meeting at work and felt lightheaded (not dizzy), thinking I was going to pass out. I remember feeling some sort of palpetation before that. Since then I've tracked my pulse and seen my GP. My pulse is often in the 50's and sometimes as low as 47. I had another episode in a meeting today. The first time, I had them call the medics. I felt better shortly after and after doing an EKG, they found nothing. I later went to emergency to get checked out...nothing. My GP has me going to see a cardiologist in a about 6 weeks. Do I need to call in the medics everytime I have one of these episodes of lightheadedness and lower heart rate? They are indeed scary but it seems pointless.