Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content +++ ECG Findings ++ Bradycardia, typically with a rate of 40 to 60 bpm. The QRS complex is narrow, < 120 ms. P waves are absent, retrograde, very slow, or unrelated to the QRS complex. +++ Pearls ++ When the atria fail to initiate a cardiac rhythm, or when no pacing signal reaches the lower AV node, the AV node or His bundle usually picks up the pacemaking responsibility. P waves may be conducted retrograde and buried in the T wave, as seen in this example. If a bundle branch block is also present, the QRS may be wide and may be difficult to discern from a primary ventricular rhythm. ++ FIGURE 23.25A Junctional Rhythm with Retrograde P Waves. (ECG contributor: James V. Ritchie, MD.) Graphic Jump LocationView Full Size||Download Slide (.ppt) ++ FIGURE 23.25B The QRS is narrow. P waves are not present before the QRS. In this example, the signal that originated in the His bundle is conducted retrograde through the AV node into the atria, and retrograde P waves are apparent in the ST segment (arrows). Graphic Jump LocationView Full Size||Download Slide (.ppt) Your Access profile is currently affiliated with [InstitutionA] and is in the process of switching affiliations to [InstitutionB]. Please select how you would like to proceed. Keep the current affiliation with [InstitutionA] and continue with the Access profile sign in process Switch affiliation to [InstitutionB] and continue with the Access profile sign in process Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Error: Incorrect UserName or Password Username Error: Please enter User Name Password Error: Please enter Password Sign in Forgot Password? Forgot Username? Download the Access App: iOS | Android Sign in via OpenAthens Sign in via Shibboleth You already have access! Please proceed to your institution's subscription. Create a free profile for additional features.