While admitting a patient to the emergency department, the nurse observes the cardiac monitor and identifies the following rhythm: one inverted P wave for every QRS complex and a regular heart rate of 46 beats per minute

Question

How would the nurse interpret this rhythm? 1. Junctional escape rhythm
2. Mobitz II heart block
3. Normal sinus rhythm
4. Complete heart block

Answer 1

1
Rationale 1: Junctional escape rhythm results from either an irritable focus in the junctional tissue that discharges before the SA node has had a chance to or because the SA node has failed to fire, making junctional node the secondary pacemaker. The impulse is initiated in the AV junctional tissue and must travel in a backward (retrograde) direction to activate the atria. Therefore, the P wave is inverted or negatively deflected and may occur before, after, or buried in the QRS complex. The intrinsic rate of the AV junction is 40 to 60 beats per minute.
Rationale 2: Mobitz II is a disturbance that occurs below the AV junction, so the P wave is normally configured.
Rationale 3: This is not normal sinus rhythm because it is not initiated by the SA node, as manifested by the inverted P wave.
Rationale 4: Complete heart block is a disturbance originating below the AV junction, so the P wave is normally configured.