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Sudden death mortality in implantable cardioverter defibrillator patients

J Gross1, P Zilo, K Ferrick

  • 1Department of Cardiothoracic Surgery, Montefiore Medical Center, Bronx, New York 10467.

Insights

Implantable cardioverter defibrillators (ICDs) reduce but do not eliminate sudden cardiac death (SCD). Arrhythmic death remains the most common cause, especially in high-risk patients receiving ICDs.

Area of Science:

  • Cardiology
  • Medical Devices

Background:

  • Sudden cardiac death (SCD) remains a significant concern.
  • Implantable cardioverter defibrillators (ICDs) are used to prevent SCD.
  • The absolute efficacy of ICDs in preventing SCD requires further investigation.

Purpose of the Study:

  • To determine the frequency and nature of SCD in patients with ICDs.
  • To analyze mortality causes in a cohort of ICD recipients.

Main Methods:

  • Retrospective review of 56 consecutive patients who underwent ICD implantation.
  • Follow-up data collected from May 1982 to May 1990.
  • Analysis of mortality incidence and causes, including SCD and arrhythmic deaths.

Main Results:

  • Twenty-one out of 56 patients died during the follow-up period.
  • Sudden cardiac death (SCD) accounted for 33% of all mortality.
  • Arrhythmic deaths represented 52% of total deaths, remaining the most common cause.
  • Cumulative SCD survival rates at 1, 3, and 5 years were 93%, 89%, and 75%, respectively.
  • All seven patients who died of SCD had experienced prior SCD events and received shocks.
  • Two of these patients had devices that were likely inactive at the time of death.

Conclusions:

  • ICDs significantly reduce but do not completely eliminate the risk of arrhythmic death.
  • Patients at the highest risk for SCD remain susceptible to arrhythmic death despite ICD implantation.
  • Device inactivity may contribute to treatment failure in some cases.

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