Comprehensive management of regular wide-QRS tachycardias in Emergency Departments

Alfonso Martín Martínez1,2 , Ignacio Fernández Lozano3

Regular wide-QRS complex tachycardia (RWQRT) in the emergency setting constitutes a diagnostic and therapeutic challenge that, due to its potential severity, requires a simultaneously rapid and precise approach. In adults, until proven otherwise, all RWQRT should be considered sustained monomorphic ventricular tachycardia (SMVT), particularly in the presence of structural heart disease, to avoid errors that delay treatment or involve inappropriate use of medications such as calcium-channel blockers. Current guidelines propose a pragmatic approach focused on identifying hemodynamic instability, early arrhythmia termination, and subsequent etiologic characterization.
From a pathophysiological perspective, SMVT mainly originates from reentry mechanisms within scar tissue regions characterized by slow conduction. Synchronized electrical cardioversion is the safest and most effective therapy and represents the “gold standard” in both hemodynamically unstable and stable patients. In the latter setting, procainamide emerges as a particularly effective therapeutic option by blocking sodium and potassium channels and acting directly on the arrhythmic mechanism. Clinical evidence, particularly from the randomized PROCAMIO trial, demonstrates that intravenous procainamide achieves higher cardioversion rates and lower incidence of adverse events compared with amiodarone in hemodynamically stable patients.
Consequently, electrical cardioversion is the most effective and safest therapy in stable wide-QRS tachycardia, whereas procainamide should be considered the pharmacologic treatment of choice, relegating amiodarone to second-line therapy and reserving lidocaine for contexts involving acute coronary ischemia. This review provides a comprehensive evaluation of the literature, integrating randomized clinical trials, observational studies, and electrophysiological principles. Based on this evidence, structured diagnostic and therapeutic algorithms are proposed, prioritizing safety and efficacy in emergency management.