This trial investigates two key aspects of the S-ICD implantation process. 1) For S-ICD implantation a pre-operative x-ray-based assessment of the anatomy and location of the heart is required. This study seeks to investigate the feasibility of US to potentially replace the need for x-ray 2) The PRAETORIAN score predicts defibrillation test success in subcutaneous ICD implantation but can only be calculated after the procedure. This pilot study aims to evaluate the feasibility of US determining the PRAETORIAN score intraoperatively. Lead-to-sternum distance and generator position measurments during the implantation procedure will be evaluated. Twenty consecutive patients scheduled for S-ICD implantation will be enrolled. The study involves no deviation from standard implantation procedures and requires no follow-up beyond standard post-operative chest X-ray on day one.

This trial investigates two key aspects of S-ICD implantation. 1) To achieve successful shock conversion of an arrhythmia with the S-ICD, the optimal position of the electrode and the device are paramount. A pre-operative x-ray-based assessment of the anatomy and location of the heart is required. Using a dummy electrode and device placed on the patient's chest, the desired position is determined through fluoroscopy, and it is marked on the patient's skin. In this trial US will be used to determine the ideal lead and device position. As the current standard, the X-ray method will then confirm ideal positioning before the device is implanted.

2) The PRAETORIAN score is an established tool to predict defibrillation test success in subcutaneous ICD implantation but can only be calculated post-procedure using chest X-ray. This pilot study aims to evaluate the feasibility of determining the PRAETORIAN score intra-operatively. This pilot study will assess whether lead-to-sternum distance and generator position can be accurately measured during the implantation procedure by manual measurements with non-fluoroscopic means. This would potentially allow risk stratification before intra-operative defibrillation testing. Ten consecutive patients scheduled for S-ICD implantation will be enrolled. The study involves no deviation from standard implantation procedures and requires no follow-up beyond standard post-operative chest X-ray on day one. If successful, this approach could improve implantation safety by identifying high-risk patients before defibrillation testing.

Inclusion Criteria:

• consecutive patients presenting for S-ICD implantation at our institution

Exclusion Criteria:

• patients unable to consent.
• pregnancy

This is a pilot study with potential proprietary data