Early repolarization associated with accelerated atrioventricular conduction (short PR interval) and incomplete right bundle branch block: postulated mechanisms

Abstract

A 36-year-old male patient, who was admitted with atypical chest pain and had normal physical examination and laboratory findings, including on an echocardiogram and a maximal exercise treadmill/thallium test, is described. His electrocardiograms (ECGs) revealed ST-segment elevation in leads V 1 through V 1, suggestive of early repolarization variant (ERPV); in addition, there was evidence of accelerated atrioventricular conduction (short PR interval) and incomplete right bundle branch block (IRBBB). It is postulated that these 2 features represent ECG “correlates” of ERPV, which is characterized by accelerated repolarization and depolarization, and are due to a rapid conduction through all or some component(s) of the atria/AV-node/Hiss bundle/left bundle branch/left ventricle “chain,” leading to a short PR interval and early and accelerated activation of the left ventricle, with resultant IRBBB. In addition to this being a case report, it constitutes a speculation that all the noted ECG findings are related and occurred in the context of ERPV; in all scientific fairness, it is possible that the accelerated atrioventricular conduction and IRBBB could have also occurred in a patient who happened to have ERPV. Finally, the occasional occurrence of morbidity and mortality in a patient with ERPV does not mitigate (at least until we know more) the time-honored belief that the ERPV is, after all, a benign ECG variant.