The Use of Direct Current Cardioversion for Unstable Atrial Fibrillation with Rapid Ventricular Response in Critically ill Patients – a Propensity Score Analysis

Objectives: There is substantial practice variation in the management strategies for atrial fibrillation (AF) with rapid ventricular rate (RVR) and hemodynamic instability in critically ill patients. This study aimed to evaluate the use and effectiveness of direct current cardioversion (DCCV) for unstable AF RVR in the intensive care unit (ICU). Design: Multicenter retrospective cohort study. Setting: Non-cardiac/cardiovascular surgery ICUs of the Mayo Clinic Hospitals in Minnesota, Wisconsin, Florida, and Arizona. Patients: Adult patients who developed paroxysmal AF RVR with hemodynamic instability (heart rate ≥ 130 beats per minute and a documented SBP ≤ 90 mmHg or the need for vasopressors) during ICU stay. Interventions: Emergency DCCV. Measurements and Main Results: Primary outcomes were in-hospital mortality, hospital-, ICU-, and organ support-free days. Secondary outcomes were return to sinus rhythm rate before and after discharge. Among 691 patients eligible for inclusion, 47 (6.8%) received emergent DCCV in the ICU. The frequency of DCCV was higher for patients located in surgical ICUs (14.5% vs 6.1%, P =.04). Patients were 1:2 propensity-score matched. The comparative analyses were conducted on 141 patients. Those who underwent DCCV were more likely to restore sinus rhythm (odds ratio [95% confidence interval], 5.2 [1.30 20.8]). However, DCCV was not associated with increased odds of having sinus rhythm at discharge, lower mortality, or higher number of ICU-, or hospital-free days. The number of organ support-free days was significantly lower in the DCCV group (estimate ± standard error, −5.0 ± 2.0, P =.012). Conclusions: Emergency DCCV is rarely used to treat unstable AF in non-cardiac ICUs. Despite increased likelihood of immediate sinus rhythm restoration, DCCV was not associated with improvement in patient-centered outcomes. Prospective studies are warranted to evaluate harms and benefits of DCCV in non-cardiac critically ill patients with unstable AF where the driver of hemodynamic instability is often an underlying condition rather than arrhythmia per se.