Sections View Full Chapter Figures Tables Videos 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 MyAccess profile is currently affiliated with '[InstitutionA]' and is in the process of switching affiliations to '[InstitutionB]'. Please click ‘Continue’ to continue the affiliation switch, otherwise click ‘Cancel’ to cancel signing in. 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 Username Error: Please enter User Name Password Error: Please enter Password Forgot Username? Forgot Password? Sign in via OpenAthens Sign in via Shibboleth