Contemporary rates of appropriate shock therapy in patients who receive implantable device therapy in a real-world setting: From the Israeli ICD Registry

Heart Rhythm. 2015 Dec;12(12):2426-33. doi: 10.1016/j.hrthm.2015.08.020. Epub 2015 Aug 13.


Background: Implantable cardioverter-defibrillators (ICDs) have become the mainstay of preventive measures for sudden cardiac death (SCD). However, there are limited data on rates of appropriate life-saving ICD shock therapies in contemporary real-life settings.

Objective: The purpose of the study was to evaluate the rate of appropriate life-saving ICD shock therapies in a contemporary registry.

Methods: The Israeli ICD Registry includes all implants and other ICD operative procedures nationwide. The present study comprises 2349 consecutive cases who were enrolled in the Registry and prospectively followed up for information regarding survival, hospitalizations, and ICD therapies since 2010.

Results: Kaplan-Meier survival analysis showed that the rate of appropriate ICD shock therapy at 30-month follow-up was 2.6% among patients who received an ICD for primary prevention compared with 7.4% among those who received a device for secondary prevention (log-rank P < .001). Rates of appropriate ICD shocks among primary prevention patients were 1.1% at 1-year of follow-up and 2.6% at 30 months, whereas the corresponding rates in the secondary prevention group were 3.8% at 1 year and 7.4% at 30 months (log-rank P < .001). A total of 253 patients (4.8%) died during follow-up, 65% of noncardiac causes.

Conclusion: Rates of life-saving appropriate ICD shock therapies among patients implanted with a defibrillator for the primary prevention of SCD in a contemporary real-world setting are lower than reported previously. These findings suggest a need for improved risk stratification and patient selection in this population.

Keywords: Appropriate shock; Defibrillator; Heart failure; Primary prevention.

MeSH terms

  • Aged
  • Cohort Studies
  • Death, Sudden, Cardiac / epidemiology
  • Death, Sudden, Cardiac / prevention & control*
  • Defibrillators, Implantable*
  • Electric Countershock* / statistics & numerical data
  • Female
  • Heart Failure / complications
  • Hospitalization
  • Humans
  • Israel / epidemiology
  • Kaplan-Meier Estimate
  • Male
  • Middle Aged
  • Registries*
  • Tachycardia / complications