Successful extravascular implantable cardioverter defibrillator implantation in a patient with ankylosing spondylitis and severe thoracic deformity: a case report

Severe thoracic deformity in ankylosing spondylitis (AS) can complicate implantable cardioverter defibrillator (ICD) implantation and device selection. Substernal EV-ICD implantation requires careful anatomical assessment and individualized procedural planning.

A 57-year-old male with severe AS and dilated cardiomyopathy was referred for primary prevention ICD implantation. Given the high complication risks associated with conventional approaches, EV-ICD was selected. A tailored positioning strategy was employed to accommodate the thoracic deformity. Intraoperative resistance during substernal dissection was successfully overcome through meticulous re-dissection. Favourable intraoperative electrical parameters were obtained, including an R-wave sensing amplitude of 5.6 mV without P-wave oversensing and successful defibrillation at 30 J on the first attempt. At 6-month follow-up, device performance remained stable without sensing anomalies or inappropriate shocks.

This case demonstrates the technical feasibility of EV-ICD implantation in a carefully selected patient with severe AS-associated thoracic deformity. Preoperative CT assessment, tailored patient positioning, careful dissection, and surgical backup enabled successful implantation and stable device performance during 6 months of follow-up.