Junctional Bradycardia

Table of Contents

Table of Contents

Published October 2020
Updated July 2021

Brandon Fainstad, MD

Assistant Professor, Department of Medicine, University of Colorado


  1. Identify a junctional rhythm based on a narrow QRS complex without a preceding P wave.
  2. Define bigeminy. 

Teaching Instructions

Preparation: Plan to spend 5-10 minutes familiarizing yourself with the animations of the PowerPoint and the key findings of this ECG.

Presentation Instructions: Present the image either by expanding the window (bottom right) in a browser or downloading the PowerPoint file (downloading is recommended).  Have the image pulled up in presenter mode before learners look at the screen to avoid revealing the diagnosis.  For each of the questions posed at the top of the slide, ask learners to discuss with their neighbor(s) for ~30 seconds.  Regroup and ask for a volunteer to share. Then advance through the animation and teaching point to the next question and repeat. You can go back to prior graphics and questions by using the back arrow or scrolling back on the mouse wheel.

Official ECG Read: Junctional escape with sinus bigeminy at a combined rate of ~40-45 bpm

Diagnosis: Severe sinus bradycardia due to nodal blockade from propranolol resulting in junctional escape and sinus bigeminy. 


  1. Junctional rhythm is defined by a regular, narrow complex without a P wave, indicating that the pacemaker is originating from the AV node or high up in the Purkinje fibers rather than from the atria (no ‘P’ wave). This is most commonly due to a diseased or suppressed SA node.
  2. Bigeminy occurs when there are two concurrent rhythms that organize into couplets. The most common scenario is a normal or increased heart rate with a sinus rhythm followed shortly with a premature atrial (PAC) or ventricular (PVC) beat that is followed by a prolonged refractory period. This case differs in that the first beat is a non-sinus escape rhythm followed by a sinus or atrial rhythm.


Take Home Points

  1. Junctional rhythm is identified by a regular, narrow complex without a ‘P' wave.  
  2. Bigeminy is due to two concurrent rhythms that organize into couplets, usually sinus followed by an ectopic rhtyhm.


Brandon Fainstad


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