Hi, I am a new member and when I read your post, I just had to respond. Along with other multiple heart conditions, I can relate to your symptoms. I have a defibrillator (pacemaker/defibrillator) due to the condition(s) you just described. A normal heart rate is 60 beats a minute or more. Any number under that is a condition known as bradycardia. You said you experience "vertigo" when your heartrate is in 30-40 range. Truely what you are experiencing is a lack of oxygen to the brain and surprisingly to me, you haven't fainted and lost consciousness yet. Please when your heart is only beating at 40 bpm (beats per minute) go to the emergency room. I also sat at home wondering if this was a serious matter or not until I passed out one day and found myself in the back of an ambulance. A heart beat this low is a very serious condition. Also the irregular heart rate needs checked out asap. These 2 symptoms were together for me. I have been diagnosed with atrial fibrillation which is an irregular heartbeat in which the top two chambers of the heart don't work in sync. However, there are other causes for irregular heartbeats. Please see family dr. asap even if you seem to be feeling fine now so he can get another EKG. Or if symptomatic, go to E.R. asap. I hope it ends up that you are just fine, but better safe than sorry. I hope I didn't scare you, but as you asked - yes, it is something to be concerned about.