Well, there are a good deal of arrhythmias that would be classified as dangerous and I'm not so certain that elucidation of those variables would relax all of you as much as it might well load the gun, so to speak. Ectopic beats are also not strictly classified as arrhythmias, but a normal variant of sinus rhythm. Technically, although it could be viewed as such, benign palpitations are actually superimposed over normal sinus rhythm, not an interruption of that rhythm.  

From a general standpoint, the difference between arrhythmias that are critical versus mere palpitations being experienced by persons on this site is that most all dangerous arrhythmias are created by circumstances within the heart or proximal cardiovascular system. Benign palpitations are merely caused by stimulation of the Vagus nerve and are not an indicator of a heart problem whatsoever. It is very important to realize this contrast because it will go a long way to help you realize that nothing is actually wrong with your heart just because a noticable symptom is detected there.

So the take home message here is that benign palpitations are not within the scope of cardiac arrhythmias, more particularly any that could be classified as dangerous. Again, just because a symptom is present, does not suggest that it represents physical disease of any kind.

Best regards and Good Health