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.