Key Points:
- The prevalence of obesity, and AF is increasing substantially and are inextricably linked.
- Patients with obesity show less response to single-DCCV due to chest wall impedance
- This trial compared dual-DCCV to single-DCCV among patients with BMI ≥ 35 in ability to attain sinus rhythm in a patient refractory to initial DCCV
- Dual-DCCV showed significantly lower rates of failure compared to single-DCCV, suggesting its utility for AF refractory to DCCV in obese patients
Prevalence of atrial fibrillation (AF) is increasing with projections of 6-16 million in 2050. This is in part due to increased rates of obesity, an AF risk factor associated with about 50% increased AF incidence, with 1 in 4 adults predicted to have a BMI ≥ 35 by 2030. Patients with obesity demonstrate higher rates of failure with direct current cardioversion (DCCV), about 25-30% compared to <10% rates of failure in patients without obesity. These higher failure rates in patients with obesity are thought to be from higher impedance secondary to increased chest wall density. Dual DCCV (using two defibrillators and two sets of pads) has previously demonstrated success in AF refractory to initial DCCV. In this trial, Aymond et al. explore whether dual DCCV demonstrates higher rates of successful cardioversion compared to single DCCV in AF patients with obesity.
The investigators conducted this multicenter randomized patient-blinded controlled trial among adult AF patients with BMI ≥ 35 on adequate anticoagulation. Patients had one set of pads placed anteriorly and posteriorly, and the other set placed anteriorly and posteriorly. Cardioversions were synchronized at 200J, with total simultaneous 400J shock in dual-DCCV patients. Patients with obesity were assigned 1:1 to single-DCCV vs dual-DCCV. If an obese patient assigned to single-DCCV failed cardioversion, dual-DCCV was tried. An obese patient assigned to dual-DCCV failed could have up to 3 attempts at cardioversion. Primary outcome was restoration of sinus rhythm, regardless of duration. Secondary outcomes were safety outcomes, specifically composite outcome of stroke, MI, or death; post-DCCV tachy- or brady-arrhythmias; and chest discomfort.
A total of 2079 patients were assessed for eligibility with ultimately 200 patients randomized total, 101 to single-DCCV, 99 to dual-DCCV. Patients’ baseline characteristics were overall comparable with the only exception of patients being slightly older in the single-DCCV arm (67.8 ± 10 vs 63.1 ± 10, p < 0.002). 36.5% of patients were women, and 19.5% identified as Black race. Average BMI among groups was 41.
This trial showed significant difference in DCCV failure rates: single-DCCV had a 14% failure rate, compared to a 2% failure rate in the dual-DCCV arm (p=0.002). The investigators found that, in a univariate analysis, dual DCCV showed success OR 7.8 (p=0.008) compared to single DCCV. With multivariate analysis limited to age, sex, and BMI, the OR increased to 8.5 (p=0.007), and when also including LVEF, LAVI, CHF, OSA, and AAD use, OR increased to 12.6 (p=0.03). With regard to safety outcomes, there was no significant difference between post-procedure chest discomfort or any procedural related adverse outcomes.
In summary, the authors concluded that for patients with obesity, with BMI ≥ 35, with AF who undergo DCCV, dual-DCCV may be more effective than single-DCCV, without increased complications or discomfort.
