LOW-ENERGY TRANSVENOUS CARDIOVERSION OF SHORT-DURATION ATRIAL TACHYARRHYTHMIAS IN HUMANS USING A SINGLE-LEAD SYSTEM

HEISEL, A., ET AL.: Low Energy Transvenous Cardioversion of Short Dura tion Atrial Tachyarrhythmias in Humans Using a Single Lead System, The purpose of this study was to investigate the efficacy and safety of a trial cardioversion using an endocardial single lead system presently used for ventricular defibrillation. The study population consisted of 26 recipients of an ICD in combination with a conventional endocardia l single lead system with the proximal spring electrode as anode in th e SVC and the distal as cathode in the apex of the RV. Atrial tachyarr hythmias were induced by right atrial burst pacing. If the arrhythmia sustained > 1 minute, biphasic shocks synchronized with the R wave wer e delivered using the implanted device, beginning with an energy of 4 J. If 4 J failed to terminate the arrhythmia, energy was increased ste pwise, if the first shock was successful, a step-down testing was perf ormed after reinduction of atrial tachyarrhythmias. The mean atrial de fibrillation threshold was 2.3 +/- 1.2 J (range, 0.5-5 J). A total of 154 shocks were delivered and no adverse effects were observed. The me an defibrillation threshold for atrial flutter was somewhat lower than that for AF (1.8 +/- 1 J vs 2.7 +/- 1.4 J, P = 0.08). There was no co rrelation between the atrial defibrillation threshold and a history of previously occurring atrial tachyarrhythmias, the kind of the underly ing heart disease, a prescription of antiarrhythmic drugs, the dimensi on of the LA, the LVEF, or the ventricular DFT. Internal atrial cardio version of short duration atrial tachyarrhythmias using a transvenous single lead system designed for ventricular defibrillation is feasible and safe at low energies, and may have important clinical application s.