High defibrillation threshold: the science, signs and solutions

Area of Science:

• Cardiovascular Electrophysiology
• Medical Device Technology

Background:

• Defibrillation threshold (DFT) testing is crucial for implantable cardioverter defibrillator (ICD) implantation.
• Increasing ICD use leads to more frequent encounters with high DFT.
• Understanding high DFT requires knowledge of defibrillation science, electrophysiological concepts, and molecular mechanisms.

Purpose of the Study:

• To provide an in-depth understanding of the science, signs, and solutions for high DFT.
• To review factors implicated in the causation of high DFT.
• To outline a step-wise algorithm for managing high DFT during ICD implantation.

Main Methods:

• Review of factors contributing to high DFT, including medical history, pharmacotherapy, lab data, and cardiac imaging.
• Analysis of drugs, procedural changes, and ICD lead systems in predicting DFT.
• Presentation of a step-wise management algorithm for high DFT.

Main Results:

• Numerous factors contribute to high DFT, necessitating comprehensive pre-procedural risk assessment.
• Specific drugs, procedural modifications, and ICD lead characteristics influence DFT during implantation.
• A structured approach is recommended when encountering unacceptably high DFT.

Conclusions:

• Managing high DFT requires a thorough understanding of underlying mechanisms and contributing factors.
• A systematic approach, starting with ruling out complications and addressing reversible derangements, is essential.
• Electrophysiologists have various device adjustment and system modification options when high DFT persists.