Is Defibrillation Testing Necessary for All ICD Implants?

Implantable cardioverter defibrillators (ICDs) have a fixed maximal energy output of between 35 and 40 joules. Because of concern that some patients require higher energies and changes in device configurations, including additional leads, patients undergoing ICD implants typically are induced into ventricular fibrillation (VF) to ensure that the ICD will recognize and terminate VF with an adequate energy safety margin. However, with current biphasic ICDs, the need for such defibrillation testing (DFT) is being challenged.

In a large, partially manufacturer-sponsored, prospective study in 18 countries, 2500 patients undergoing left-sided ICD implant for standard indications were randomized to undergoing DFT or not. The primary outcome was a c…