Impact of a novel algorithm designed to reduce T-wave oversensing with the subcutaneous defibrillator in a patient with type I Brugada electrocardiogram

This patient case underscores the clinical value of S-ICD as an alternative solution for younger patients, who need multiple years of ICD therapy, for sudden cardiac death prophylaxis. Introduction Brugada syndrome (BrS) is an inherited disease associated with an increased risk of developing malignant ventricular arrhythmias. These can not only cause syncope but also lead to sudden cardiac death (SCD), which may be the first manifestation of the syndrome. The type I electrocardiogram (ECG) is typically characterized by ST-segment elevation of more than 2 mm (coved type) in at least one of the right precordial leads. The most common gene mutation is associated with the SCN5A locus and found in 20%–25% of patients with BrS. While implantable cardioverter-defibrillator (ICD) therapy is the main therapy in symptomatic patients, a low arrhythmic event rate is often observed and the relatively high complication risk in mostly young patients who receive transvenous ICDs (TV-ICDs) should be taken into account when considering this approach. Common complications in these patients are inappropriate shocks, mainly due to T-wave oversensing, caused by spontaneous ECG variability, which increases the risk of false detection. Despite its existing detection algorithms, the morphologybased subcutaneous sensing approach of the subcutaneous ICD (S-ICD) has been vulnerable to QRS/T-wave oversensing, which is the leading cause of inappropriate shocks with the S-ICD. This phenomenon occurs more often in patients with spontaneous type I Brugada ECGs. Conversely, many of the system-related complications of TV-ICDs can be avoided by the S-ICD: with a device-related complication–free rate of 99% and which is considered a favorable therapy, over TV-ICD therapy, in young patients.