Clinical impact of defibrillation testing in a real‐world S‐ICD population: Data from the ELISIR registry

Abstract

Background Current guidelines recommend defibrillation testing (DT) performance in patients with a subcutaneous implantable cardioverter defibrillator (S‐ICD), theoretically to reduce the amount of ineffective shocks. DT, however, has been proven unnecessary in transvenous ICD and real‐world data show a growing trend in avoidance of DT after S‐ICD implantation. Methods All patients undergoing S‐ICD implant at nine associated Italian centers joining in the ELISIR registry (http://ClinicalTrials.gov Identifier: NCT04373876) were enrolled and classified upon DT performance. Long‐term follow‐up events were recorded and compared to report the long‐term efficacy and safety of S‐ICD implantations without DT in a real‐world setting. Results A total of 420 patients (54.0 ± 15.5 years, 80.0% male) were enrolled in the study. A DT was performed in 254 (60.5%) patients (DT+ group), while in 166 (39.5%) was avoided (DT− group). Over a median follow‐up of 19 (11–31) months, a very low rate (0.7%) of ineffective shocks was observed, and no significant differences in the primary combined arrhythmic outcome were observed between the two groups (p = .656). At regression analysis, the only clinical predictor associated with the primary combined outcome was S‐ICD placement for primary prevention (odds ratio: 0.42; p = .013); DT performance instead was not associated with a reduction in primary outcome (p = .375). Conclusion Implanting an S‐ICD without DT does not appear to impact the safety of defibrillation therapy and overall patients' survival.

Intraprocedural PRAETORIAN score for early assessment of S‐ICD implantation: A proof‐of‐concept study

“…Preliminary reports have shown that routine DT during S-ICD implantation may not represent an effective modality to assess the conversion effectiveness of S-ICDs. 10,14,15 This is mostly due to the…”

“…Since its development, a lower PRAETORIAN score has been associated with an optimal placement of the device, while a higher risk class has been shown to correlate with ineffective defibrillation in a real-world setting. [8][9][10] Although recent, this tool has often been used in recent studies addressing S-ICD placement and it represents a clinical reality for many "device teams." [8][9][10][11][12][13] As this tool is currently perceived, however, it represents a postprocedural evaluation, which can only lead to an early (but not immediate) S-ICD repositioning when a high risk of conversion failure is detected, requiring a full reintervention and resulting into patient discomfort and a second need for an operating theater access.…”

“…[8][9][10] Although recent, this tool has often been used in recent studies addressing S-ICD placement and it represents a clinical reality for many "device teams." [8][9][10][11][12][13] As this tool is currently perceived, however, it represents a postprocedural evaluation, which can only lead to an early (but not immediate) S-ICD repositioning when a high risk of conversion failure is detected, requiring a full reintervention and resulting into patient discomfort and a second need for an operating theater access. The aim of this proof-of-concept study was to assess the feasibility of an intraprocedural use of the PRAETORIAN score, which might be capable to overcome these issues.…”

“…The PRAETORIAN score integrates into a single value an assessment of the technical aspects most related to an adequate S-ICD placement, including a correction for BMI as well. Initially, it has been presented as a novel tool allowing to screen for a high risk of conversion failure in patients with S-ICD, with the potential of being an alternative to routine DT performance 7,10. Afterward, as highlighted in a recent study from van der Stuijt et al,12 device repositioning at generator replacement in selected patients with an intermediate-to-high risk of conversions failure was performed, to achieve a reduction of PP-PS.The main critique moved to the routine use of PRAETORIAN score has been its postprocedural implementation, that actually limits its clinical impact on procedure guidance, thus potentially leading to early reintervention when it results high.…”

A 10 J shock impedance in sinus rhythm correlates with a 65 J defibrillation impedance during subcutaneous defibrillator implantation using an intermuscular technique

“…Despite this class I recommendation, many implanting physicians defer DT for S-ICD. Based on the early experience with S-ICD in the United States extracted from the National Cardiovascular Data Registry ICD Registry between 2012 and 2015, Friedman et al reported a steadily declining trend of DT during S-ICD implantation (87.7% in 2012and 67.5% in 2015)2 In the recent multi-center Italian ELISIR registry, DT was performed only in 60.5% of new S-ICD implants 21. During a median follow-up of 19 months, there was no difference in the composite outcome of mortality, inappropriate shocks, and conversion failure between patients with and without DT at the time of implant.…”