The Implantable Cardioverter Defibrillator

The Defibrillation Safety Margin of Patients Receiving ICDs: A Matter of Definition

“…Gold 13 has emphasized that the goal of defibrillation testing is to ensure that the maximal energy output of the ICD has an extremely high (>99%) probability of terminating ventricular fibrillation in a given patient. On this basis, Gold 13 defined the safety margin for programming (in the legend of his published defibrillation success curves) as the difference between the measured DFT and the E99 point, or as he indicates the energy needed for greater than 99% successful defibrillation. This definition of “safety margin” corresponds with the “efficacy margin” of Singer and Lang 9 and suggests that Gold believes that above the E99 point, the additional energy is probably not helpful.…”

Foreseeable variation in parameters measured at implant and follow-up of permanent pacemaker active fixation electrodes

“…After 48 h we recorded significant variations in other values such as the ventricular and atrial pacing thresholds, with improvement of these parameters; a new decrease in impedance that could contain artifacts due to the different ways of recording the values through the generator, or to local endomyocardial lesion phenomena 16 ; and a decrease in the intrinsic activity values. Posteriorly, the values are seen to stabilize and show a more linear behavior over the long term than in the first few days.…”