The Low Energy Safety Study (LESS): rationale, design, patient characteristics, and device utilization.

Background: A 10-J energy safety margin has traditionally been used in programming implantable cardioverter defibrillators (ICDs). The Low Energy Safety Study (LESS) tests the hypothesis that programming shocks to lower energy margins is safe and effective.

Methods: Patients with standard ICD indications undergo defibrillation threshold testing (DFT) at the time of ICD implant, with reconfirmation of lowest successful energy twice (DFT++).