Successful implantation of an extravascular implantable cardioverter-defibrillator in a patient with moderate pectus excavatum: a case report.

Background: Implantable cardioverter-defibrillators (ICDs) prevent sudden cardiac death due to ventricular arrhythmia. A novel extravascular ICD (EV-ICD) system provides improved functionality over previous transvenous (TV-ICD) and subcutaneous (S-ICD) alternatives, particularly in younger patients. This includes limited bradycardia pacing, anti-tachycardia pacing therapy, and lower energy defibrillation, all within a smaller device profile compared to the S-ICD. Due to the need for substernal lead placement, however, complex sternal anatomy is currently considered a relative contraindication to their use. Case summary: We present a 38-year-old male patient with pectus excavatum and a previous episode of ventricular fibrillation leading to out-of-hospital cardiac arrest. Initial implantation of a S-ICD was associated with repeated inappropriate shocks over 4 years, leading to multidisciplinary discussions with the patient regarding off-label use of an EV-ICD, as approved by Medtronic CRM. Explantation of the S-ICD and implantation of the EV-ICD were successful, with minimal technical changes required compared to standard surgical technique in normal sternal anatomy. At 6-month follow-up, there were no complications or inappropriate shocks. Discussion: The EV-ICD may be considered in patients with pectus excavatum, making this novel device available to a larger proportion of patients. Aside from careful consideration of instrument positioning during the procedure, this can be done with minimal changes to the standard surgical protocol.