Defibrillation testing during implantation of the subcutaneous implantable cardioverter-defibrillator: a necessary standard or becoming redundant?

Abstract

Since the publication of the SIMPLE and NORDIC trials, defibrillation testing (DFT) is rarely performed during routine implantation of transvenous implantable cardioverter-defibrillators (ICD). However, the results of these trials cannot be extrapolated to the later introduced subcutaneous ICD (S-ICD) and a class I recommendation to perform DFT during the implantation of these devices remains in the current guidelines. Due to the high conversion success rate of DFT on one hand, and the risk of complications on the other, a significant number of physicians omit DFT in S-ICD recipients. Several retrospective analyses have assessed the safety of the omission of DFT and report contradicting results and recommendations. It is known that implant position, as well as device factors and patient characteristics, influence defibrillation success. A better comprehension of these factors and their relationship could lead to more reliable and safer alternatives to DFT. An ongoing randomised clinical trial, which is expected to end in 2023, is the first study to implement a method that assesses implant position to identify patients who are likely to fail their DFT.

Propofol dose and efficacy of defibrillation testing during implantation of subcutaneous implantable cardioverter‐defibrillators: A retrospective, single center cohort study

“…The ratio of first shock termination (85%) seemed low, but is well in line with pre-existing data when analyzing the first shock. 5 Gold et al reported a successful defibrillation in 91.2% with a shock energy of ≤65 J in 1412 patients. 23 The higher rate may be due to sedation differences and a higher rate of general anesthesia, especially when considering the four patients with successful first shock 2 days after implantation.…”

“…There are few studies that have investigated factors affecting the success of DFT in S-ICD implantation. 5 These include shock output, implant position, amount of fat tissue, impedance and large chest circumference. 5,[24][25][26][27] We tried to represent the amount of fat tissue and large chest circumference by including the BMI, showing no association with first shock termination.…”

“…3,4 In contrast, DFT, with first shock energy of 65 J, is still routinely recommended after S-ICD implantation, as adequate studies demonstrating the safety of omitting DFT are still lacking. 5 Scores able to predict effective defibrillation depending on a correct device positioning are being validated. 3,6 The implantation of S-ICD systems, differently from TV-ICD, requires either deep sedation or general anesthesia.…”

Subcutaneous implantable cardioverter-defibrillator and defibrillation testing: A propensity-matched pilot study

“…Additionally, DT performance requires anesthesiologic support and, although uncommon, complications associated with DTs have been reported 10,17,18 . Hence, the possibility of forgoing DT after S-ICD implantation has been postulated 19 .…”

Real-Life Inter-Rater Variability of the PRAETORIAN Score Values

“…According to the experimental and clinical research, it has been determined that the defibrillation threshold of the S-ICD system may be associated with the following risk factors: the final position of the system (specifically regarding the amount of fat tissue under the coil of the lead, the amount of fat tissue under the device, and placement of the S-ICD generator anteriorly on the thoracic wall) and high body mass index (BMI) [ 11 , 12 , 13 ]. Therefore, the PRAETORIAN score (PS) was developed, based on those factors, to quantify the possible risk of failed DFT [ 14 , 15 ].…”