Implantable Cardioverter-Defibrillator Therapies Following Generator Replacements-Long-Term Remote Monitoring Data

Background: The rate of long-term outcomes, including arrhythmic episodes following implantable cardioverter-defibrillator (ICD) device replacements, is often unknown. Thus, the aim of this manuscript was to evaluate the risk of ICD or cardiac resynchronization therapy-defibrillator (CRT-D) therapies in remotely monitored patients following device replacement. Methods: Data from 134 patients who underwent ICD/CRT-D replacement or upgrade were analyzed. Kaplan-Meier estimates, as well as Cox proportional hazards regression, were used to present long-term outcomes and predictors of study endpoints, these being all-cause mortality, and appropriate and inappropriate ICD/CRT-D therapies. Results: Among the cohort, 51.5% of patients received ICDs and 48.5% received CRT-Ds; the median (quartile 1-quartile 3) LVEF at replacement was 23.0% (18.0-28.0%). In 11 (8.2%) patients, the LVEF at replacement was higher than 35%. During the median (Q1-Q3) follow-up of 3.0 (1.4-5.0) years, 32.1% experienced appropriate and 6.0% experienced inappropriate therapies. The all-cause mortality rate was 38.0%, and appropriate antitachycardia pacing (ATP), a reduced baseline LVEF, and no history of myocardial infarction were independent predictors of death (odds ratios of 1.87 for appropriate ATP, 0.88 per 1% of the LVEF and 0.54 for a history of MI, respectively). The rate of appropriate device therapies was numerically lower in patients whose LVEF improved (19.8% vs. 33.3% and 0% vs. 6.5%, for appropriate and inappropriate therapies). An LVEF of >35% at replacement did not influence the analyzed outcomes. Conclusions: In patients who underwent ICD/CRT-D replacement, an improvement in LVEF was not identified as either a predictor of improved survival or of a lower risk of needing device therapies. Further stratification models are needed to evaluate the arrhythmic risk in patients after generator replacements.