Time Of Generator Replacement Research Articles

Proof Positive

The administration of prophylactic antibiotics before pacemaker or internal cardioverter-defibrillator implantation has been implemented widely and routinely. The acceptance of this practice has occurred despite the absence of rigorous examination or definitive evidence. The existing data for the use of prophylactic antibiotic therapy in device implantation consist of 7 randomized, controlled trials, with all but 1 having an open design.1 Early trials yielded contradictory results, citing small study numbers, a low incidence of infection, and inconsistent definitions of infection as possible explanations.2–4 Four of the 7 trials found antibiotic prophylaxis effective in preventing infection; the lone double-blind, randomized, controlled study consisted of 106 patients and failed to demonstrate a difference in infection rate with antibiotic prophylaxis because there were no documented infections at 7 to 35 months of follow-up.3 In addition to their inconsistent results, widely varying antibiotic regimens were implemented in these trials, further confounding the ability of operators to interpret the available data and to implement evidence-based medicine into practice. Despite the equivocal findings of these individual studies, a meta-analysis of antibiotic prophylaxis for permanent pacemaker implantation by Da Costa et al1 in 1998 demonstrated a significant reduction …

431 Long term complications of implantable cardioverter defibrillators near or at the time of generator replacement

431 Long term complications of implantable cardioverter defibrillators near or at the time of generator replacement

431 Long term complications of implantable cardioverter defibrillators near or at the time of generator replacement

431 Long term complications of implantable cardioverter defibrillators near or at the time of generator replacement

Long‐Term Internal Cardiac Defibrillation Threshold Stability

The automatic implantable cardioverter-defibrillator is tested intraoperatively with defibrillation trials to ensure effectiveness. It is unknown if the energy requirement for internal defibrillation remains stable and that once demonstrated effective, if the device will continue to be effective in terminating lethal ventricular arrhythmias. In this study, the defibrillation energy requirement was compared in 56 patients at the time of lead implantation to that obtained at the time of generator replacement. Mean time to generator replacement was 17. +/- 6.6 months. The defibrillation threshold was stable over that time (11.9 +/- 6.7 joules compared to 12.7 +/- 8.4 joules, NS). There was no relation between transmyocardial impedance and defibrillation threshold. In addition, no effect on defibrillation threshold was demonstrated by the use of various cardiac medications, concomitant surgery or the occurrence of clinical shocks during follow-up.

An evaluation of long-term stimulation thresholds by measurement of chronic strength duration curve.

Successful long-term cardiac pacemaker therapy requires both reliable generator output and stable, attainable chronic stimulation thresholds. Strength duration curves, which display cardiac stimulation thresholds as a function of impulse duration, provide needed data to evaluate more thoroughly acute and chronic lead thresholds. We measured chronic strength duration curves at the time of generator replacement in 47 patients with three different types of lead systems of variable geometry and surface area and compared these curves with acute strength duration curves measured at the time of initial implantation in 19 patients. We found that strength duration curves has a characteristic shape; however, chronic strength duration curves were shifted upward and to the right of acute strength duration curves, regardless of electrode tip surface area or geometric design. Our data suggest that variable pulse width exceeding 1 ms may not significantly reduce stimulation thresholds.