I don't have enough information to comment on if it is dangerous.
It would depend on lots of other data like: heart function,
EKGAtrioventricular block, ekg tracing
Ecg
Exercise stress test, heart disease or no heart disease (coronary disease).
I am concerned about the symptoms of shortness of breath, but again, there is a lot of information necessary to determine the cause of shortness of breath and if it could be cardiac. It is important to discuss these symptoms with your doctor and ask them that direct questions about whether the arrhythmia is dangerous.