Recurrent Sudden Cardiac Arrest in the General Population

Objective: To evaluate the burden and determinants of recurrent out-of-hospital sudden cardiac arrest (SCA) in the community. Background: Despite improvements in management of SCA survivors and wide availability of implantable defibrillators for secondary prevention, a subgroup of individuals will suffer multiple distinct episodes of SCA. Methods: SCA cases were prospectively ascertained in the Oregon Sudden Unexpected Death Study. Individuals that experienced recurrent SCA were identified both prospectively and retrospectively. We conducted detailed comparisons with survivors of single SCA events. Results: We ascertained 6649 individuals with SCA from 2002-2020 and 924 (14%) survived to hospital discharge. Of these, 123 survivors (13%) experienced recurrent SCA (age 61.9 {plus minus} 14.0 at first event; 69% male; median time interval 22 months). Compared with SCA survivors who suffered a single event (n=302), patients with recurrent SCA had lower rates of receiving implantable cardioverter-defibrillators (ICD; 58%vs. 22%, p<0.001) and 60% of events occurred later than one year following initial SCA. Among a subset of individuals with recurrent SCA and no secondary prevention ICD (n=70), the majority had apparently reversible etiologies, with one-quarter undergoing coronary revascularization and over half diagnosed with non-coronary etiologies. Recurrent SCA subjects were more likely to have a history of diabetes (44% vs 25%, p<0.001) and kidney disease (35% vs 13%, p<0.001). Conclusions: A sizeable subset of SCA survivors (13%) had recurrent SCA, and diabetes and renal disease were identified as predictors of increased risk. These findings highlight the critical importance of comprehensive SCA risk prediction, and apparently reversible etiologies need renewed scrutiny.