No, it is not dangerous. A normal heart rate falls between 60-100 bpm for a normal person. Chances are you were experiencing anxiety at only 112 bpm. If you reduce your stress and anxiety and your heart rate remains over 100 bpm, that is considered abnormal, but in of itself not dangerous. A medical work up would be advised to rule out an arrhythmia. Your heart can beat 200 bpm for 24 hours before it will harm your heart.