Ask Dr. Z

I understand that code 93655 can be billed more than once when both arrhythmias are "discrete mechanisms". My question is, what exactly does it mean by discrete mechanisms? I do know that if one is A-flutter and another is another sort of SVT that would make them each distinct. But how about when both arrhythmias are the same kind (A-flutter) oroginating from different locations, for example, one LEFT mitral annular flutter and one RIGHT atrial flutter? Would these be considered "separate mechanisms?"