CC BY-NC-ND 4.0 · Journal of Cardiac Critical Care TSS 2020; 4(02): 140-143
DOI: 10.1055/s-0040-1718986
Case Report

Phenytoin-Induced Cardiac Conduction Abnormalities

Glen Brown
1  Pharmacy Department, St. Paul’s Hospital, Vancouver, British Columbia, Canada
Wesley Jang
2  Critical Care Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
Adam Peets
3  Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
Krishnan Ramanathan
4  Division of Cardiology, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
› Author Affiliations
Funding No financial support was necessary for the preparation of this manuscript.


Phenytoin possesses electrophysiological effects consistent with those of the Vaughan–Williams 1B classification. As such, phenytoin may widen the QRS complex but would not be expected to result in QTc prolongation or ST elevation. The reported case demonstrates these unexpected electrophysiological effects with supratherapeutic concentrations of phenytoin when no other potential cause could be elucidated. No contributing factors present in the case, compared with previously published reports of electrophysiological effects of supratherapeutic phenytoin concentrations, could be elucidated. The report suggests that clinicians should monitor for potential conduction abnormalities in patients with elevated phenytoin concentrations.

Publication History

Publication Date:
01 November 2020 (online)

© 2020. Official Publication of The Simulation Society (TSS), accredited by International Society of Cardiovascular Ultrasound ISCU. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (

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