ELECTRICAL CARDIOVERSION AND DEFIBRILLATION IN THE MANAGEMENT OF CARDIAC ARRHYTHMIAS: PHYSIOLOGICAL FOUNDATIONS, TECHNICAL ASPECTS, CLINICAL PERFORMANCE, AND COMPLICATIONS

Abstract

Cardiac arrhythmias constitute a broad clinical spectrum, ranging from benign disorders to potentially fatal conditions, in which electrical cardioversion and defibrillation have become central interventions in elective and emergency management. This article aims to synthesize the physiological fundamentals, technical aspects, clinical performance, and main complications associated with these procedures, based on an integrative narrative literature review. Electrical reversion is based on the simultaneous depolarization of the myocardium to interrupt reentry circuits and restore sinus rhythm, differing in the synchronization of the discharge and the clinical indication. Synchronized cardioversion is mainly used in supraventricular arrhythmias and monomorphic ventricular tachycardia, while unsynchronized defibrillation is reserved for ventricular fibrillation and pulseless ventricular tachycardia, with synchronization with the R wave being a critical safety element. The success of reversion depends on factors such as the type and duration of the arrhythmia, the presence of structural heart disease, and technical parameters, including waveform, initial energy charge, and electrode placement, with overall success rates between 70% and 90%. In atrial fibrillation, electrical reversion is not superior to rate control in major clinical outcomes, requiring individualized management and appropriate anticoagulation, while in malignant ventricular arrhythmias, the time to the first discharge is the main prognostic determinant. Complications include transient electrocardiographic changes, benign arrhythmias, systemic embolization, and transient myocardial dysfunction, reinforcing the need for rigorous preparation and continuous monitoring. It is concluded that electrical cardioversion and defibrillation are essential and safe interventions when well indicated, with performance conditioned by clinical and technical variables, and gaps remain regarding the ideal standardization of parameters and long-term outcomes.