Abstract 6993: Electrical Storm in Patients Without an Implantable Cardioverter-Defibrillator is Associated With Higher In-Hospital All-Cause Mortality

Abstract

Introduction: Most data regarding electrical storm (ES) is retrospective from implantable cardioverter-defibrillator (ICD) interrogation, little is known about outcomes in those without an ICD. Objective: Primary outcomes include all-cause in-hospital and 6-month mortality of ES comparing patients with and without ICDs. Secondary outcomes include in-hospital complications. We hypothesize that ES patients without ICDs will have a worse short term prognosis with higher rates of in-hospital complications. Methods: Retrospective single center study including all patients admitted to the coronary ICU with ES between April 2014 - 2020. ES was defined as ≥ 3 isolated sustained ventricular arrhythmias (VA) or ICD therapies within 24 hours. Results: Of 214 patients admitted with ES, 37 did not have an ICD. For those with an ICD, the mean time from implantation to ES was 1101.1 ± 928.4 days. Those without ICD were less likely to be male (70.3% vs. 85.9%; p = 0.029), have known coronary artery disease (37.8% vs. 55.9%; p=0.049), or prior VA (5.4% vs. 84.7%; p<0.0001). Those without ICDs had a higher ejection fraction (39% ± 16% vs. 30% ± 12%; p=0.002), lower PAINESD risk score (14.3 ± 7.3 vs. 17.5 ± 6.2; p=0.004), and were more likely to present with out-of-hospital cardiac arrest (43.2% vs. 5.1%; RR 8.5, 95% CI 4.1 - 17.8; p<0.001). Those without ICDs were more likely to develop complications including SCAI stage D-E cardiogenic shock (RR 2.58, 95% CI 1.9 - 3.5; p<0.001), multiorgan failure (RR 3.78, 95% CI 2.1 - 6.7; p<0.0001), and in-hospital cardiac arrest (RR 4.10, 95% CI 2.7 - 6.2; p<0.0001). Those without ICDs were more likely to have polymorphic ventricular tachycardia (PMVT; 62.2% vs. 23.2%; RR 2.68, 95% CI 1.9 - 3.9; p<0.0001) or ventricular fibrillation (VF; 56.8% vs. 24.9%; RR 2.28, 95% CI 1.6 - 3.3; p=0.0003). In-hospital all-cause (29.7% vs. 13.0%; RR 2.29, 95% CI 1.2 - 4.3; p=0.023) and VA-induced (27.0% vs. 11.3%; RR 2.39, 95% CI 1.2 - 4.7; p=0.019) mortality was higher in patients without ICDs, although 6-month mortality was not significant (Log Rank X 2 1.24; p=0.27). Conclusions: Patients without ICDs were more likely to present following out-of-hospital cardiac arrest with underlying PMVT or VF morphologies. They had higher in-hospital complications and mortality.