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document
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++ ) . Patients are randomized to 2 groups : the first has the initial 2 shocks for ventricular fibrillation conversion programmed at 2 energy steps above DFT++ ( typically 4-6 J , maximum 10 J ) with subsequent shocks at maximum energy , and the second has all shocks programmed at maximum energy . Patients are followed up every 3 months for 2 years to assess shock conversion efficacy of spontaneous arrhythmias . In a subgroup of patients , there is a second randomization to energy levels of 0 , 1 , 2 , 3 , or 4 steps above implant DFT++ for conversion testing of 3 induced ventricular fibrillation episodes at prehospital discharge , 3 months , and 12 months after implant . RESULTS Enrollment is complete ( 702 patients ) , but follow-up results are pending . There were no significant variations in implant indications and baseline antiarrhythmic drug use over the 3-year enrollment period , although an increase in the percentage of dual-chamber ICDs implanted occurred , with the majority ( 65 % ) of implanted ICDs being dual-chamber devices by the end of the enrollment period . CONCLUSION The results of LESS should facilitate the development of algorithms for programming ICD energy safety margins .
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Intervention_Physical
Low Energy Safety Study
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Intervention_Physical
implantable cardioverter defibrillators
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Intervention_Surgical
( ICDs )
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Intervention_Physical
Low Energy Safety Study
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Intervention_Physical
defibrillation threshold testing ( DFT )
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Intervention_Physical
ICD implant
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Intervention_Physical
initial 2 shocks for ventricular fibrillation conversion programmed at 2 energy steps above DFT++ ( typically 4-6 J , maximum 10 J ) with subsequent shocks at maximum energy
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Intervention_Physical
all shocks programmed at maximum energy
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Intervention_Physical
DFT++
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Intervention_Pharmacological
antiarrhythmic drug
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Outcome_Physical
shock conversion efficacy of spontaneous arrhythmias
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Outcome_Physical
implant indications and baseline antiarrhythmic drug use
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Outcome_Physical
percentage of dual-chamber ICDs implanted
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Outcome_Physical
energy safety margins
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Outcome_Other
.
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Participant_Condition
implantable cardioverter defibrillators
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Participant_Condition
ICDs
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Participant_Condition
Patients with standard ICD indications
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Participant_Condition
ICD implant
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Participant_Sample-size
702