Patient Care Technician (PCT) AAH Practice Exam

What characterizes a Premature Junctional Contraction (PJC)?

1. Regular R-R intervals with absent QRS

2. Inverted or absent P waves with irregular R-R intervals

3. P wave and QRS are always present

4. Prolonged PRI preceding a QRS complex

The correct answer is: Inverted or absent P waves with irregular R-R intervals

A Premature Junctional Contraction (PJC) is characterized primarily by the presence of an inverted or absent P wave, along with irregular R-R intervals. This arises due to an ectopic focus in the junctional tissue, which can lead to the heart initiating a contraction before the next expected beat from the sinoatrial (SA) node, resulting in irregularity in the timing of contractions. In a PJC, the typical characteristics include the absence of the normal P wave that is associated with atrial depolarization or an inverted P wave that occurs after the QRS complex. Moreover, because PJCs disrupt the normal rhythm, there can be variability in the R-R intervals, reflecting the early occurrence of the beat. The other choices do not accurately describe the characteristics of a PJC. The presence of regular R-R intervals with an absent QRS is not consistent with this condition, as PJCs typically have QRS complexes that arise following the premature electrical activity. Having a P wave and QRS always present does not represent PJCs, since one of the defining features is the abnormality of the P wave. Lastly, a prolonged PRI preceding a QRS complex is not characteristic of PJCs, as this finding is more associated with