AP-518-01 SUBCUTANEOUS IMPLANTABLE CARDIOVERTER DEFIBRILLATOR SMART DEACTIVATION INCREASES INAPPROPRIATE SHOCKS, A REAL-WORLD SINGLE CENTRE EXPERIENCE

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The SICD has been increasingly used with its addition to the HRS guidelines in 2017. A question mark remains around the burden of inappropriate therapy (IT), which, in PRETORIAN had an IT in 9.6% of patients over 4 years. Importantly, this trial was conducted using devices without the SMART pass (SP) algorithm installed. SP (Boston Scientific Corporation, Natick, MA) is a bandpass filter has been shown to reduce inappropriate therapy. However, a key area under-investigated is the algorithms’ ability to deactivate itself in community. We aimed to assess: the effect of SP, with clinical variables, on inappropriate therapies and oversensing; why the device deactivates SP and how best to manage this scenario, in a large, single centre. A retrospective audit of all Emblem S-ICD devices (A209 & A219) implanted from 2016 to 2020 using data from electronic pacing & health records and latitude remote monitoring system. The baseline clinical characteristics and SICD programming were recorded at implant and throughout follow up. A total of 322 patients were reviewed with a follow up of 27 months ± 16.6 months. 234were primary prevention (73%) and remaining 88 patients (27%) were secondary prevention. Thirty-eight (11.8%) of patients received total of 83 shocks. Twenty-four (7.5%) patients receiving IT, totalling 44 shocks. One IT was due to aberrant AF, the remaining 43 were due to oversensing. SP was a significant predictor of all therapy (p.00049) and IT (p.009). Table 1 shows rate of SP deactivation and IT rate. SP deactivation has an odds ratio of 6.45 (95% CI: 2.62 to 15.94) of IT. SP deactivation was due to low R waves in 19 patients, significant asystole in 1 patient and not available in 1 patient at the time of therapy. SP deactivation is a significant predictor and marker of IT. If the SP filter is deactivated this is likely to suggest low amplitude sensing signals. To reduce the risk of IT the cause of the SP deactivation should be investigated and sensing vector changes should be strongly considered. If the SP algorithm continues to de-activate, lead reposition should be considered, similarly to a transvenous RV ICD lead would for poor sensing. An alert for SP deactivation, R wave size and raw S-EGMs would provide clinicians with appropriate decision making to prevent IT.