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Mortality Risk Increases With Clustered Ventricular Arrhythmias in Patients With Implantable Cardioverter-Defibrillators

2020; Elsevier BV; Volume: 6; Issue: 3 Linguagem: Inglês

10.1016/j.jacep.2019.11.012

2405-5018

Ihab Elsokkari, Ratika Parkash, Anthony Tang, George A. Wells, Steve Doucette, Elizabeth Yetisir, Martin J. Gardner, Jeff S. Healey, Bernard Thibault, Laurence D. Sterns, David H. Birnie, Pablo B. Nery, Soori Sivakumaran, Vidal Essebag, Paul Dorian, John L. Sapp,

Cardiac electrophysiology and arrhythmias

This study sought to examine the adverse prognosis associated with ventricular arrhythmia clusters that falls outside the current electrical storm definition.Electrical storm is most frequently defined as a cluster of ≥3 episodes of ventricular arrhythmia (VA) in a 24-h period. This definition has been associated with adverse cardiovascular outcomes and mortality, but the effect of lesser and greater clustering of arrhythmias has not been described.Among all patients in the Resynchronization in Ambulatory Heart Failure trial, 14,515 implantable cardioverter-defibrillator-detected events with data available were rigorously adjudicated in blinded fashion. Arrhythmia incidence was examined for clustering, defined as 2 or more VA events occurring within 3 months. The prognostic importance of clustering was analyzed by varying the cluster length and number of events used to define a cluster. Mortality rates of groups with clustered arrhythmias were compared to patients with no arrhythmia or with unclustered arrhythmia.The trial included 1,764 patients, among whom 465 patients had two or more VA episodes within 3 months, whereas 406 had unclustered arrhythmias. Compared to patients with no arrhythmia, patients experiencing unclustered VA had increased risk of death (hazard ratio [HR]: 1.45; 95% confidence interval [CI]: 1.09 to 1.93; p = 0.011), whereas the risk was even higher in patients with clustered arrhythmia (HR: 2.68; 95% CI: 2.13 to 3.36; p < 0.0001). Mortality risk increased with higher VA burden (number of VAs in a cluster) and shorter cluster length. This was observed in all groups tested, including the cluster with the least VA burden in the longest cluster length tested (2 VA episodes occurring within 3 months) (mortality HR: 2.85; 95% CI: 1.95 to 4.17; p < 0.0001). Although clustered arrhythmias terminated with antitachycardia pacing were associated with increased mortality, clusters terminated with implantable cardioverter-defibrillator shocks were associated with still higher mortality risk.Significant adverse prognostic association of clustered VAs is observable with even 2 VA events within 3 months and increases with higher cluster density.