Transvenous atrial defibrillation--techniques and clinical applications.

Atrial fibrillation (AF) is the most common arrhythmia requiring treatment. The most desirable therapy may be restoration and maintenance of sinus rhythm. Limitations of the current methods for cardioversion of AF have prompted the development of transvenous atrial defibrillation (TADF) as an alternative and more effective technique for converting AF. Recent advances in the technique of TADF, particularly in the design and configuration of the electrodes, and the use of an optimal biphasic shock waveform have dramatically improved the efficacy of TADF for the termination of all types of AF. The reduction in voltage and energy requirements for cardioversion by TADF may allow the procedure to be performed with little or no sedation and the risk of general anesthesia may be avoided. Both experimental and clinical studies have demonstrated the feasibility, safety, and efficacy of using TADF as a new temporary or "permanent" mode of electrical therapy for AF. It has several potential applications, from acute termination of AF in the electrophysiology laboratory and in patients who have failed to respond to external cardioversion, to its use as an implantable device for treating recurrent AF. This article reviews the current technique and clinical applications of TADF for treatment of AF.