Cardiac resynchronization therapy (CRT) is a well-established treatment of patients with advanced heart failure and electrical dyssynchrony. Implantation of those devices is in some cases associated with intervention on a formerly implanted system. The aim of this analysis was to compare the rate and type of complications of de novo implants and upgrades to CRT-D. Retrospective data were collected from medical records, including 326 patients treated with CRT-D between 2015 and 2020. The following data were analyzed: procedure data including complications, demographics, co-morbidities, pharmacotherapy, and laboratory tests. The primary endpoint of the study was all-cause mortality. A total of 326 procedure were included, of which 53% (n = 172) were de novo implants and 47% (n = 154) were upgrades. The groups did not differ in the incidence of complications: in the de novo group: 25.5% (n = 44); in the upgrade group: 30.5% (n = 47), p = 0.78. The incidence of complications was also similar in respect of the following: early (p = 0.98) and late (p = 0.45), infectious (p = 0.38) and non-infectious (p = 0.82), surgical (p = 0.38) and device or lead related (p = 0.6). The most common complication in the upgrade group was pocket hematoma (n = 9, 5.8%) and in the de novo group pneumothorax (n = 8, 4.7%). Upgrade procedures of are not associated with a higher percentage of complications than de novo implantations of CRT-D. Previously implanted cardiac implantable electronic device should not limit the implantation of CRT-Ds.