Device updates successfully reduce T‑wave oversensing and inappropriate shocks in subcutaneous ICD patients

R Larbig; L J Motloch; M Bettin; A Fischer; N Bode; G Frommeyer; A Loeher; J Koebe; F Reinke; L Eckardt

doi:10.1007/s12471-018-1160-y

Device updates successfully reduce T‑wave oversensing and inappropriate shocks in subcutaneous ICD patients

Neth Heart J. 2018 Dec;26(12):606-611. doi: 10.1007/s12471-018-1160-y.

Authors

R Larbig¹, L J Motloch², M Bettin³, A Fischer³, N Bode³, G Frommeyer³, A Loeher⁴, J Koebe³, F Reinke³, L Eckardt³

Affiliations

¹ Division of Electrophysiology, Department of Cardiovascular Medicine, University of Muenster, Muenster, Germany. Robert.Larbig@gmx.de.
² Department of Internal Medicine II, Paracelsus Medical University, Salzburg, Austria.
³ Division of Electrophysiology, Department of Cardiovascular Medicine, University of Muenster, Muenster, Germany.
⁴ Department of Cardiac and Thoracic Surgery, University of Muenster, Muenster, Germany.

Abstract

Aims: To analyse the impact of device and software updates on the prevention of T‑wave 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 S‑ICD patients who were implanted between 2010 and 2016. In all eligible consecutive patients (n = 139), follow-up of at least 6 weeks was studied. The incidence of TWOS/IS was analysed in patients receiving a 2^nd generation S‑ICD (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 S‑ICD implantation were similar in both groups. However, the cumulative incidence of TWOS/IS was significantly decreased in Emblem vs. SQ (SQ: 15.4%, n = 14/91 vs. Emblem 4.2%, n = 2/48; p = 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%, n = 11/82 vs. after update: 4.6%, 3/65, p = 0.07).

Conclusion: 2^nd generation devices but probably also the SMR8 software update reduce the incidence of TWOS/IS in S‑ICD patients.

Keywords: Inappropriate shocks; Oversensing; S-ICD.