P wave oversensing and rate-related bundle branch block with T wave oversensing leading to inappropriate S-ICD therapies in cardiac sarcoidosis: A case report.

Subcutaneous implantable cardioverter defibrillators (S-ICDs) are increasingly implanted devices to prevent sudden cardiac death (SCD), whether as a primary or secondary prevention strategies especially in patients who are at risk of developing complications related to transvenous implantable cardioverter defibrillators (TV-ICDs) and without an indication for cardiac pacing. However, S-ICDs can deliver inappropriate shocks due to sensing abnormalities, despite the applied strategies to prevent this complication. We present a case of a 56-year-old patient with cardiac sarcoidosis who experienced inappropriate shocks due to T wave oversensing (TWOS) secondary to rate related aberrancy and P wave oversensing. To the best of our knowledge, this is the first reported case of inappropriate S-ICD therapy in cardiac sarcoidosis, which highlights the necessity of closely monitoring the patient to prevent sensing abnormalities as the pre-implant screening cannot accurately predict future QRS alterations that might lead to oversensing and inappropriate shocks.