Validation and clinical implications of higher intercostal space electrocardiography in the patient with Brugada syndrome in Taiwan (SADS-TW BrS registry).

Background: Diagnosis of Brugada syndrome (BrS) is based on type 1 morphology (coved type) in electrocardiograms from standard (4th) or higher (2nd or 3rd) intercostal spaces (ICSs). However, the clinical implications of being diagnosed only at higher ICSs remains poorly understood. We aimed to investigate the diagnostic accuracy of higher ICS leads in the Taiwanese Brugada syndrome population and clarify if there is any difference in clinical presentation. Method: Patients enrolled in the Sudden Arrhythmic Death Syndrome-Taiwan (SADS-TW) registry from 2010/01/01 to 2021/07/30 were retrospectively reviewed. Records were examined for 163 patients whose ECGs in the 2nd, 3rd, and/or 4th ICSs showed a type 1 BrS pattern in at least 1 lead. Baseline characteristics, family history, clinical presentation, SCN5A mutation status, cardiovascular events, and mortality were analyzed. Result: Using the standard ICS alone, 56.4% patients could be diagnosed with BrS, whereas the remaining 43.6% of patients could only be diagnosed using higher ICSs. The mean age of diagnosis using higher ICSs was 42.2 ± 14.7 years vs. 46.8 ± 14.6 years in patients diagnosed using the standard ICSs (p = 0.048). Hypertension was more prevalent in patients diagnosed by standard ICSs (27.2%) vs. patients diagnosed by higher ICSs (4.2%; p < 0.001). No differences were observed in family history, clinical presentation, SCN5A mutation status, cardiovascular events, or mortality (mean follow-up time = 3.96 ± 3.45 years, p = 0.28). Conclusion: Using higher intercostal leads could significantly increase the diagnosis rate of BrS in the Taiwanese population, although it would not affect the clinical prognosis.