RESUMO
AIMS: To analyse the impact of device and software updates on the prevention of Twave oversensing (TWOS) and inappropriate shocks (IS) in subcutaneous ICD (S-ICD) patients. BACKGROUND: TWOS is a feared complication after implantation. It may lead to harmful IS. To date, specific strategies to reduce these events are lacking. METHODS: In this retrospective single-centre trial we analysed 146 SICD patients who were implanted between 2010 and 2016. In all eligible consecutive patients (nâ¯= 139), follow-up of at least 6 weeks was studied. The incidence of TWOS/IS was analysed in patients receiving a 2nd generation SICD (Emblem-S-ICD) between 2014 and 2016 (Emblem). Their outcome was compared with a control group (SQ) treated with the SQ1010 device between 2010 and 2014, who were followed up for a maximum of 2 years. Furthermore, to test if the software update SMR8 reduces inappropriate shocks in the SQ1010-S-ICD population, the incidence of TWOS/IS was evaluated before and after update installation. RESULTS: Basic characteristics and indications for SICD implantation were similar in both groups. However, the cumulative incidence of TWOS/IS was significantly decreased in Emblem vs. SQ (SQ: 15.4%, nâ¯= 14/91 vs. Emblem 4.2%, nâ¯= 2/48; pâ¯= 0.049). Furthermore, with regards to the SQ population we also observed a trend towards a significant reduction of TWOS/IS after installation of the software update SMR8 in 2014 (before update: 13.4%, nâ¯= 11/82 vs. after update: 4.6%, 3/65, pâ¯= 0.07). CONCLUSION: 2nd generation devices but probably also the SMR8 software update reduce the incidence of TWOS/IS in SICD patients.