Related Experiment Video
Updated: Aug 24, 2026

Dual-Dye Optical Mapping of Hearts from RyR2R2474S Knock-In Mice of Catecholaminergic Polymorphic Ventricular Tachycardia
Published on: December 22, 2023
Case of polymorphic ventricular tachycardia in diphenhydramine poisoning
Ajay K Joshi1, Tatjana Sljapic, Hassan Borghei
1Division of Cardiovascular Diseases, Lankenau Hospital and Institute for Medical Research, Main Line Health Heart Center, Wynnewood, Pennsylvania, USA.
Abstract:
This is the first reported case of torsades de pointes attributable to diphenhydramine, a drug with weak I(Kr) effects. A 26-year-old, healthy man was admitted to intensive care after a diphenhydramine overdose. Results of physical examination, ECG, and electrolytes were normal at admission. Despite supportive care, he developed typical, sustained, torsades de pointes with a markedly prolonged QT interval requiring cardioversion. Drugs with weak I(Kr)-blocking effects may cause lethal proarrhythmia in susceptible individuals when delivered in high concentrations. This case illustrates the variation in repolarization reserve that exists in a free-standing population.
Related Concept Videos
Toxidromes: Clinical Features
Dysrhythmias II: Classification of Tachyarrhythmias
ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias
Desensitization and Tachyphylaxis
Several...
Dysrhythmias III: Characteristics of Dysrhythmias
Pharmaceutical Poisoning: Potential Scenarios
