A novel tool to evaluate the implant position and predict defibrillation success of the subcutaneous implantable cardioverter-defibrillator: The PRAETORIAN score

Anne-Floor B. E. Quast, Sarah W. E. Baalman, Tom F. Brouwer, Lonneke Smeding, Arthur A. M. Wilde, Martin C. Burke, Reinoud E. Knops

Research output: Contribution to journalArticleAcademicpeer-review

91 Citations (Scopus)

Abstract

Background: Suboptimal positioning of the subcutaneous implantable cardioverter-defibrillator (S-ICD) increases the defibrillation threshold and risk of conversion failure. Objective: Our objective is to develop a tool to evaluate the implant position and predict defibrillation success of the S-ICD: the PRAETORIAN score. Methods: The PRAETORIAN score is based on clinical and computer modeling knowledge of determinants affecting the defibrillation threshold: subcoil fat, subgenerator fat, and anterior positioning of the S-ICD generator. The score evaluates these determinants on the postoperative anterior-posterior and lateral chest radiographs and has 3 categories: 30–<90 points representing a low risk, 90–<150 points representing an intermediate risk, and ≥150 points representing a high risk of conversion failure. The score was developed using 2 separate S-ICD data sets for derivation and validation. The performance metrics are the positive and negative predictive values. Results: The development data set consisted of 181 patients with S-ICD, and the validation cohort consisted of 321 patients from the S-ICD Investigational Device Exemption trial. The distribution of scores was 93%–98% low risk (<90 points), 2%–5% intermediate risk (90–<150 points), and 1% high risk (≥150 points). The positive predictive value for an intermediate or high PRAETORIAN score for a failed conversion test was 51%, while a low PRAETORIAN score predicted a successful conversion in 99.8% of patients. Conclusion: The PRAETORIAN score allows the identification of patients with high defibrillation thresholds by using the routine chest radiograph and provides feedback to implanters on S-ICD positioning. The PRAETORIAN-DFT trial will prospectively validate the score by randomizing to standard conversion testing vs using the score without conversion testing.
Original languageEnglish
Pages (from-to)403-410
JournalHeart Rhythm
Volume16
Issue number3
Early online date2018
DOIs
Publication statusPublished - 2019

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