Which rhythm is characterized by random, early junctional beats with QRS 0.10 s or less and typically a long compensatory pause?

Which rhythm is characterized by random, early junctional beats with QRS 0.10 s or less and typically a long compensatory pause?

• A. Junctional Escape Rhythm
• B. Accelerated Junctional Escape Rhythm
• C. Idioventricular Rhythm
• D. Premature Junctional Contraction

Answer: (D)

Premature junctional contraction is an ectopic beat that starts in the AV junction and occurs earlier than the next expected beat. Because the impulse travels through the normal ventricles, the QRS complex remains narrow (0.10 s or less). The P wave, if visible, may be inverted, absent, or appear retrograde, and the beat often resets the pacing cycle, producing a longer-than-normal pause before the next regular beat. This combination—an early, junctional impulse with a narrow QRS and a relatively long pause after the beat—fits the described pattern best. The other rhythms lack one or more of these features: they are not premature junctional beats, they have wide QRS when ventricular origin is involved, or they represent automatic escape rhythms rather than premature ones.

Premature junctional contraction is an ectopic beat that starts in the AV junction and occurs earlier than the next expected beat. Because the impulse travels through the normal ventricles, the QRS complex remains narrow (0.10 s or less). The P wave, if visible, may be inverted, absent, or appear retrograde, and the beat often resets the pacing cycle, producing a longer-than-normal pause before the next regular beat. This combination—an early, junctional impulse with a narrow QRS and a relatively long pause after the beat—fits the described pattern best. The other rhythms lack one or more of these features: they are not premature junctional beats, they have wide QRS when ventricular origin is involved, or they represent automatic escape rhythms rather than premature ones.