Currently, the usual initial strategy for direct current cardioversion (DCCV) typically involves delivering 200J of electricity between two pads placed in the anterior and posterior positions (i.e., one on the chest and one on the back). However, this technique may be less likely to result in successful cardioversion in obese patients (BMI ≥30 kg/m2). Failure to achieve sinus rhythm then necessitates additional shocks, which still may ultimately fail to terminate the patient's atrial fibrillation, thereby increasing the likelihood of adverse events from multiple cardioversion attempts

"Dual-DCCV" is a technique in which four pads are used to deliver two simultaneous shocks of 200J, totaling 400J. Guidelines published by the American Heart Association/American College of Cardiology/Heart Rhythm Society and the European Society of Cardiology provide only general guidance regarding the appropriate technique and energy selection in patients undergoing cardioversion, with no specific recommendations pertaining to dual-DCCV or obese patients.

This study aims to assess the safety and efficacy of dual-DCCV as an initial treatment strategy, compared to standard single-DCCV, in the obese population.

Patients with sustained atrial fibrillation and obesity who are scheduled for a cardioversion for atrial fibrillation will provide written informed consent prior to starting the procedure. Patients will be randomly assigned in a 1:1 fashion to either single-DCCV or dual-DCCV treatment.

All patients will have 4 defibrillation pads placed: two pads placed in the right infraclavicular region and left flank region, plus two pads placed in the left infraclavicular and right flank region.

All patients will receive moderate sedation immediately prior to and during cardioversion.

Patients randomized to single-DCCV will be given a single 200J shock using the "primary" (or right anterior-left posterior) pair of pads. Patients assigned to dual-DCCV will receive two simultaneous 200J shocks (from both the "primary" and "secondary" set of defibrillator pads), totaling 400J delivered.

Patients in the single-DCCV group whose initial shock fails to restore normal sinus rhythm will be crossed over to the dual-DCCV group. Patients in the dual-DCCV group will receive up to three attempts at DCCV, as needed, at the discretion of the attending electrophysiologist.

One hour after cardioversion is completed, patients will be asked if they experienced any chest discomfort related to cardioversion and, if applicable, will rate their chest discomfort using a pain scale from 0-10.

Inclusion Criteria:

• 18 years of age

• Atrial fibrillation (paroxysmal, persistent, and long-standing persistent)

• Obesity (defined as body mass index [BMI] ≥35 kg/m2). Of note, our current institutional protocol uses weight >250 lbs as an indication for dual-DCCV. An average height of 70 inches equates to BMI ~35 kg/m2

• Adequate anticoagulation at the time of the cardioversion (one of the following):

  • Coumadin with an INR >2
  • Direct oral anticoagulants (apixaban, dabigatran, rivaroxaban, or edoxaban)
  • Subcutaneous low molecular-weight heparin or IV unfractionated heparin

• If the duration of atrial fibrillation is >48 hours (or unknown): trans-esophageal echocardiography (TEE) performed prior to cardioversion to document the absence of a left atrial thrombus, or continuous therapeutic anticoagulation for a minimum of 3 weeks prior to cardioversion

• Able to maintain uninterrupted therapeutic anticoagulation after cardioversion, for at least one month

Exclusion Criteria:

• Contraindication to cardioversion
• Not on adequate anticoagulation
• Emergent cardioversion
• Incarceration
• Pregnancy

All patients will have 4 defibrillation pads placed: two pads placed in the right infraclavicular and left flank regions, plus two pads placed in the left infraclavicular and right flank regions. Patients will not be told which arm they are randomized to during the procedure.