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Defibrillation threshold (DFT) testing

An ICD & CRT Therapy term on the RCES exam blueprint, defined for cath lab and EP clinicians.

Historically performed at implant by inducing VF and confirming the device successfully detects and terminates it at a safety margin below the device's maximum output; modern practice has moved toward more selective DFT testing (not universally required) given strong safety margins built into contemporary devices, but understanding the rationale and protocol (sedation/anesthesia support, induction method, safety standby external defibrillation) remains a core competency.

Domain: ICD & CRT Therapy · Blueprint: RCES exam guide

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Written and reviewed by John-Philip (JP) Maarschalk, BSN, RN, CNML — a nurse manager who runs operations for the cardiac cath lab, electrophysiology, and interventional service lines at an academic health system in North Carolina. He hires and develops the staff who sit for these exams. More about JP and how this content is made →
Cardiac Codex is an independent study tool published by MdoubleA LLC, not affiliated with or endorsed by CCI or any certifying body. This glossary entry is exam-preparation information, not medical advice or a substitute for clinical judgment. Always verify current clinical practice against primary sources and institutional protocol.