The subcutaneous implantable cardioverter-defibrillator (S-ICD; Boston Scientific, Marlborough, MA) was designed as an alternative to a traditional transvenous ICD (TV-ICD) to avoid complications associated with transvenous lead implantation 1 Kipp R. Hsu J.C. Freeman J. Curtis J. Bao H. Hoffmayer K.S. Long-term morbidity and mortality after implantable cardioverter-defibrillator implantation with procedural complication: A report from the National Cardiovascular Data Registry.

Heart Rhythm Jun. 2018; 15: 847-854

,2 Ranasinghe I. Parzynski C.S. Freeman J.V. et al. Long-Term Risk for Device-Related Complications and Reoperations After Implantable Cardioverter-Defibrillator Implantation: An Observational Cohort Study.

Ann Intern Med Jul 5. 2016; 165: 20-29

and extraction. 3 Bardy G.H. Smith W.M. Hood M.A. et al. An entirely subcutaneous implantable cardioverter-defibrillator.

N Engl J Med Jul 1. 2010; 363: 36-44

The S-ICD has demonstrated to be non-inferior in respect to device-related complications or inappropriate shocks in patients without an indication for pacing. 4 Knops R.E. Olde Nordkamp L.R.A. Delnoy P.H.M. et al. Subcutaneous or Transvenous Defibrillator Therapy.

N Engl J Med Aug 6. 2020; 383: 526-536

However, certain challenges remain such as a higher rate of inappropriate shocks, 5 Olde Nordkamp L.R. Brouwer T.F. Barr C. et al. Inappropriate shocks in the subcutaneous ICD: Incidence, predictors and management.

Int J Cardiol. Sep 15 2015; 195: 126-133

limited data on defibrillation testing at the time of generator change, 6 Rudic B. Tulumen E. Fastenrath F. Akin I. Borggrefe M. Kuschyk J. Defibrillation failure in patients undergoing replacement of subcutaneous defibrillator pulse generator.

Heart Rhythm Mar. 2020; 17: 455-459

and suboptimal aesthetics; particularly in younger and smaller patients. These considerations have led to evolving implantation techniques, which include a two rather than three incision strategy for lead placement. 7 Knops R.E. Olde Nordkamp L.R. de Groot J.R. Wilde A.A. Two-incision technique for implantation of the subcutaneous implantable cardioverter-defibrillator.

Heart Rhythm Aug. 2013; 10: 1240-1243

Additionally, modern generator implant techniques have migrated away from a traditional subcutaneous position to a preferred intermuscular position with the pulse generator (PG) positioned between the posterior surface of the latissimus dorsi and the anterior surface of the serratus anterior. 8 Ferrari P. Giofre F. De Filippo P. Intermuscular pocket for subcutaneous implantable cardioverter defibrillator: Single-center experience.

J Arrhythm Jun. 2016; 32: 223-226

,9 Migliore F. Allocca G. Calzolari V. et al. Intermuscular Two-Incision Technique for Subcutaneous Implantable Cardioverter Defibrillator Implantation: Results from a Multicenter Registry.

Pacing Clin Electrophysiol Mar. 2017; 40: 278-285

The preferred deeper positioning offers the potential of improved device efficacy by minimizing space between the PG and thoracic cavity. 10 Quast A.B.E. Baalman S.W.E. Brouwer T.F. et al. A novel tool to evaluate the implant position and predict defibrillation success of the subcutaneous implantable cardioverter-defibrillator: The PRAETORIAN score.

Heart Rhythm Mar. 2019; 16: 403-410

Additionally, superior aesthetics is expected due to deeper positioning, particularly in those with a smaller body habitus where the generator may appear prominent.