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Aims Device-related infection (DRI) is a severe complication to cardiac implantable electronic devices (CIED) therapy. Device-related infection incidence and its risk factors differ between previous studies. We aimed to define the long-term incidence and incidence rates of DRI for different types of CIEDs in the complete Danish device-cohort and identify patient-, operation- and device-related risk factors for DRI. Methods and results From the Danish Pacemaker (PM) and implantable cardioverter-defibrillator (ICD) Register, we included consecutive Danish patients undergoing CIED implantation or reoperation from January 1982 to April 2018, resulting in 97 750 patients, 128 045 operations and follow-up of in total 566 275 device years (DY). We identified 1827 DRI causing device removals. Device-related infection incidence during device lifetime was 1.19% (1.12–1.26) for PM, 1.91% (1.71–2.13) for ICD, 2.18% (1.78–2.64) for cardiac resynchronization therapy (CRT)-pacemakers (CRT-P), and 3.35% (2.92–3.83) for CRT-defibrillators (CRT-D). Incidence rates in de novo implantations were 2.04/1000 DY for PM, 3.84 for ICD, 4.38 for CRT-P, and 6.76 for CRT-D. Using multiple-record and multiple-event per subject proportional hazard analysis, we identified implantation of complex devices (ICD and CRT), reoperations, prior DRI, male sex, and younger age as significantly associated with higher DRI risk. Conclusion Overall risk of infection was low in PM implantations but considerably higher in CRT systems and after reinterventions. These data support the importance of evaluating all patients considered for CIED therapy thoroughly, in order to identify potential modifiable risk factors and reduce the risk of early reoperations.

Background: The PRAETORIAN trial showed non-inferiority of the subcutaneous implantable cardioverter-defibrillator (S-ICD) compared to the transvenous ICD (TV-ICD) with regard to inappropriate shocks and complications. In contrast to the TV-ICD, the S-ICD cannot provide antitachycardia pacing (ATP) for monomorphic ventricular tachycardia (VT). This pre-specified secondary analysis evaluates appropriate therapy and whether ATP reduces the number of appropriate shocks. Methods: The PRAETORIAN trial was an international, investigator-initiated randomized trial, which included patients with an indication for ICD therapy. Patients with prior VTs below 170 bpm or refractory recurrent monomorphic VTs were excluded. In 39 centers, 849 patients were randomized to receive an S-ICD (N=426) or TV-ICD (N=423) and were followed for a median of 49.1 months. ICD programming was mandated by protocol. Appropriate ICD therapy was defined as therapy for ventricular arrhythmias. Arrhythmias were classified as discrete episodes and storm episodes (≥3 episodes within 24 hours). Analyses were performed in the modified intention-to-treat population. Results: In the S-ICD group, 86/426 patients received appropriate therapy, versus 78/423 patients in the TV-ICD group, during a median follow-up of 52 months (48-month Kaplan-Meier estimates 19.4% and 17.5%, P=0.45). In the S-ICD group, 83 patients received at least one shock, versus 57 patients in the TV-ICD group (48-month Kaplan-Meier estimates 19.2% and 11.5%, P=0.02). Patients in the S-ICD group had a total of 254 shocks, compared to 228 shocks in the TV-ICD group (P=0.68). First shock efficacy was 93.8% in the S-ICD group and 91.6% in the TV-ICD group (P=0.40). The first ATP attempt successfully terminated 46% of all monomorphic VTs, but accelerated the arrhythmia in 9.4%. Ten S-ICD patients experienced 13 electrical storms, versus 18 TV-ICD patients with 19 electrical storms. Patients with appropriate therapy had an almost two-fold increased relative risk of electrical storms in the TV-ICD group compared to the S-ICD group (P=0.05). Conclusions: In this trial, no difference was observed in shock efficacy of the S-ICD compared with the TV-ICD. Although patients in the S-ICD group were more likely to receive an ICD shock, the total number of appropriate shocks was not different between the two groups.

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