Document Type
Article
Publication Date
5-20-2026
Abstract
CASE SUMMARY: A 73-year-old man with severe aortic stenosis and preexisting right bundle branch block (RBBB) underwent transcatheter aortic valve replacement. Postprocedural day 4 mobile cardiac outpatient telemetry revealed intermittent atrioventricular block. A 12-lead electrocardiogram obtained in the emergency department revealed PR interval alternans with RBBB, with longer PR following longer preceding RP intervals, and shorter PR following shorter RP intervals. He suddenly experienced cardiac arrest due to proximal atrioventricular block, requiring cardiopulmonary resuscitation.
TAKE-HOME MESSAGES: Inverse decremental conduction, known as Yan conduction, demonstrates an inverse relationship between conduction time and frequency of upstream stimulation. Inverse decremental conduction within the left bundle branch in the setting of RBBB may manifest as PR alternans, heralding proximal atrioventricular block.
Recommended Citation
Zakala, Alyssa; Hussein Kamareddine, Mohammed; Olleik, Farah; Keramati, Ali; and Yan, Gan-Xin, "PR Interval Alternans and the Mystery of Inverse Decremental Conduction" (2026). Department of Medicine Faculty Papers. Paper 568.
https://jdc.jefferson.edu/medfp/568
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
PubMed ID
42165478
Language
English
Comments
This article is the author's final published version in JACC: Case Reports, Volume 31, Issue 20, May 2026, Article Number 107935.
The published version is available at https://doi.org/10.1016/j.jaccas.2026.107935. Copyright © 2026 The Authors.