Abstract 55: Ventricular Fibrillation remains the Primary Presenting Rhythm: Results from the Wearable Cardioverter Defibrillator Human Study
Background. Clinical studies during the last 2 decades have demonstrated a progressive decrease in the incidence of ventricular fibrillation (VF) as the presenting rhythm in settings of out-of-hospital sudden cardiac arrest (SCA). In the present study, we investigated the initial rhythm of SCA from data recorded in a wearable cardioverter defibrillator (WCD) which collected these events in real time.
Hypothesis. In settings of out-of-hospital SCA, VF remains the leading cause.
Methods and Results. The incidence and the type of arrhythmias were determined by reviewing stored electrocardiograms in the WCDs. Seventy-four consecutive WCD recipients and 108 events were analyzed. Patients with a previously implanted ICD that required change due to infection were the most prevalent recipients of WCDs. Fifty-one percent were VF/VT patients and 43.8% were pulseless electrical activity (PEA) patients. VF/VT was the initial rhythm of SCA in 79.7% of patients and 86.1% of events while the PEA occurred in 20.3% of patients and 13.9% of events. 84.5% of patients survived VF/VT and 18.8% of patients survived PEA. There was no difference in the characteristics of patients with different initial rhythms.
Conclusions. In out-of-hospital settings, VF remains the predominant initial rhythm when recorded immediately following SCA. .