Frequency and Determinants of ICD Deployment among Primary Prevention Candidates with Subsequent Sudden Cardiac Arrest in the Community
Background—The prevalence rates and influencing factors for deployment of primary prevention implantable cardioverter defibrillators (ICDs) among subjects that eventually suffer sudden cardiac arrest (SCA) in the general population, have not been evaluated.
Methods & Results—Adult SCA cases with echocardiographic evaluation prior to the event were identified from the ongoing Oregon Sudden Unexpected Death Study (Population approximately 1 million). Eligibility for primary ICD was determined from medical records based on established guidelines. The frequency of prior primary ICD implantation in eligible subjects was evaluated, and ICD non-recipients were characterized. Out of 2093 cases (2003-2012), 448 had appropriate pre-SCA LV ejection fraction (EF) information available. Of these, 92 (20.5%) were eligible for primary ICD, 304 (67.9%) ineligible due to LVEF> 35% and the remainder (52, 11.6%) had LVEF ≤ 35%, but were ineligible based on clinical guideline criteria. Among eligible subjects, only 12 (13.0%; 95% CI 6.1% - 19.9%), received a primary ICD. Compared to recipients, primary ICD non-recipients were older (age at EF assessment 67.1 ± 13.6 vs. 58.5 ± 14.8, p=0.05), with 20 % aged ≥ 80 years (vs. 0% among recipients, p =0.11). Additionally, a subgroup (26%) had either a clinical history of dementia or was on chronic dialysis.
Conclusions—Only one-fifth of the SCA cases in the community were eligible for a primary prevention ICD before the event, but among these a small proportion (13%) was actually implanted. While older age and comorbidity may explain non-deployment in a subgroup, other determinants such as socioeconomic factors, health insurance, patient preference and clinical practice patterns warrant further detailed investigation.
- Received March 11, 2013.
- Revision received August 16, 2013.
- Accepted August 21, 2013.