Premature Junctional Contraction rhythm differs from normal rhythm by what feature?

• A. The presence of a premature junctional beat
• B. Prolonged QT interval
• C. Wide QRS complexes
• D. Presence of P waves before every beat

Answer: (A)

Premature Junctional Contractions are defined by an early beat that originates in the AV junction rather than the SA node. Because the impulse starts near the AV node, the QRS complex remains narrow, since ventricular conduction is normal. The hallmark is the premature timing of this junctional beat, which disrupts the regular rhythm. P waves associated with a premature junctional beat often don’t appear before the QRS and may be inverted or hidden within the QRS, so the normal pattern of a P wave preceding every beat is altered.

Prolonged QT interval is not what sets PJCs apart; it reflects a different repolarization issue. Wide QRS complexes point to a ventricular origin or aberrant conduction, not typical PJCs. Presence of P waves before every beat describes a normal sinus rhythm, not a rhythm with premature junctional activity.