Background: Implantable cardioverter defibrillator (ICD) therapy is expensive, but cost effectiveness has been demonstrated over longterm follow-up. Short-term mortality negatively impacts cost-effectiveness and ICD therapy is contraindicated in patients with expected longevityrecipients.

Methods: Patients who underwent initial ICD implant from 2008-14 within the Aurora Health Care network (Wisconsin and northern Illinois) with at least 3 years of follow-up and/or suffered the primary endpoint of death were evaluated. Cox regression was used to determine hazard ratios (HR) for significant predictors identified through forward stepwise analysis.

Results: In our ICD population (n=1560), total mortality was 194 (12.9%) and 42 patients died within 1 year of ICD implant (2.8%, 21.6% of total mortality). Clinical characteristics at the time of initial ICD implant that emerged as predictors of mortality included bradycardic arrest (HR 9.06, p70 (HR=2.39, p100 not meeting left bundle branch block [BBB] or right BBB criteria; HR 1.90, p

Conclusions: A small but substantial percentage of central Midwestern ICD patients are at risk for 1-year mortality, and 1/5 of our total ICD mortality occurred within 1 year of implant. Several clinical characteristics at initial ICD implant predict mortality, including 1-year mortality, in our large cohort. Applying a priori knowledge of predictors of mortality, particularly 1-year mortality, may improve patient selection and cost-effectiveness of ICD therapy.