Final answer:
The correct answer is c. Less irregular. PJT typically presents with a more rapid heart rate compared to sinus tachycardia, and an EKG showing an increased frequency between QRS complexes suggests a faster pulse, important for distinguishing between different types of tachycardias.
Step-by-step explanation:
PJT stands for Paroxysmal Junctional Tachycardia, which is an abnormal heart rhythm characterized by a rapid heart rate. To distinguish PJT from sinus tachycardia, a usual EKG feature of PJT is a less regular rate.
A normal heart rhythm is characterized by a consistent and regular rate, while PJT will have irregular intervals between the QRS complexes on the EKG. This irregularity in the heart rate helps differentiate it from sinus tachycardia, which would have a more regular rate.