The relationship between defibrillation threshold and total mortality.

Area of Science:

• Cardiology
• Medical Devices
• Electrophysiology

Background:

• The prognostic significance of defibrillation threshold (DFT) in patients with implantable cardioverter-defibrillators (ICDs) remains incompletely understood.
• Investigating the correlation between DFT and overall mortality is crucial for patient management.

Purpose of the Study:

• To determine if implant DFT is an independent predictor of mortality in patients receiving ICDs.
• To explore the relationship between varying levels of implant DFT and patient survival outcomes.

Main Methods:

• A prospective analysis of 508 patients undergoing ICD implantation with recorded DFT.
• Patients were stratified into three groups based on implant DFT: high (≥20 J), moderate (19-11 J), and low (≤10 J).
• Survival data and potential confounding factors were collected and analyzed over a mean follow-up of 3.2 years.

Main Results:

• A total of 140 deaths occurred during the follow-up period.
• The high DFT group exhibited a significantly higher mortality rate (35.8%) compared to the moderate (28.7%) and low (24.0%) DFT groups (p=0.05).
• Implant DFT emerged as a significant independent predictor of mortality (p=0.004), alongside age, LVEF, CAD, amiodarone use, and hematoma at implant.

Conclusions:

• Elevated implant DFT is associated with an adverse prognosis and predicts increased mortality risk.
• This association persists even when an adequate safety margin for ICD function is confirmed.
• The findings underscore the importance of considering implant DFT as a prognostic marker in ICD patients.