Double Sequential External Defibrillation in Patients With Atrial Fibrillation Refractory to DC Cardioversion

Atrial fibrillation (AF) is a common cardiac arrhythmia that leads to increased risk of heart failure, hospitalization, thromboembolic events, and death. Restoration of normal heart rhythm is performed in many patients with AF to improve symptoms. In this study, the investigators will consider patients who fail 2 or more trials of DC cardioversion as having refractory AF. The aim of this study is to assess whether the use of double sequential defibrillation in patients with refractory AF has a higher success rate in reverting them to a normal heart rhythm than a third cardioversion. This is a phase III, randomized controlled, single-centered, superiority trial. All patients with AF admitted to the coronary care unit (CCU) for DC cardioversion, and refractory to at least two trials of DC cardioversion will be enrolled. Patients are randomized into two arms: the first will receive a third trial of DC cardioversion (standard of care) and the second will receive double sequential external defibrillation. The resolution of AF by reverting back to normal sinus rhythm is the primary outcome of the investigators. This will be determined using EKG (electrocardiogram) immediately after DC cardioversion or double sequential defibrillation.

Patients presenting to the CCU with persistent AF for direct current (DC) cardioversion, who meet the inclusion criteria and fail to revert to normal sinus rhythm after two DC cardioversion attempts will be invited for enrollment in the study. No sampling will be carried out for the sake of this study. Patients meeting the eligibility criteria will receive double sequential external defibrillation (DSED) or a third DC cardioversion (standard of care). DSED is the process of using two defibrillators near simultaneously at their highest allowed energy setting and aims to treat refractory atrial fibrillation. The first set of pads is placed in the traditional anterolateral position and the second set can be either placed adjacent to the first set (antero-lateral) or in the antero-posterior position. Shocks are then delivered simultaneously or near simultaneously.