Contributor: Travis Barlock MD Educational Pearls: Wide-complex tachycardia is defined as a heart rate > 100 BPM with a QRS width > 120 milliseconds Wide-complex tachycardia of supraventricular origin is known as SVT with aberrancy Aberrancy is due to bundle branch blocks Mostly benign Treated with adenosine or diltiazem Wide-complex tachycardia of ventricular origin is also known as VTach Originates from ventricular myocytes, which are poor inherent pacemakers Dangerous rhythm that can lead to death Treated with amiodarone or lidocaine 80% of wide-complex tachycardias are VTach 90% likelihood for patients with a history of coronary artery disease In assessing a wide-complex tachycardia, it is best to treat it as a presumed ventricular tachycardia Treating SVT with amiodarone or lidocaine does no harm  However, treating VTach with adenosine or diltiazem may worsen the condition References 1. Littmann L, Olson EG, Gibbs MA. Initial evaluation and management of wide-complex tachycardia: A simplified and practical approach. Am J Emerg Med. 2019;37(7):1340-1345. doi:https://doi.org/10.1016/j.ajem.2019.04.027 2. Viskin S, Chorin E, Viskin D, Hochstadt A, Schwartz AL, Rosso R. Polymorphic Ventricular Tachycardia: Terminology, Mechanism, Diagnosis, and Emergency Therapy. Circulation. 2021;144(10):823-839. doi:10.1161/CIRCULATIONAHA.121.055783 3. Williams SE, O’Neill M, Kotadia ID. Supraventricular tachycardia: An overview of diagnosis and management. Clin Med J R Coll Physicians London. 2020;20(1):43-47. doi:10.7861/clinmed.cme.20.1.3 Summarized by Jorge Chalit, OMSIII | Edited by Meg Joyce & Jorge Chalit