Positioning of the egc leads in Brugada Syndrome: higher sensitivy with lower specificity? Answers from a genetically characterized family

Introduction There is concordant opinion that upward displacement of V1, V2, and V3 leads increases the number of ECGs that are diagnostic for the Brugada Syndrome (BS). There are no data that prove whether this manoeuvre increases the sensitivity of the diagnosis without affecting its specificity. Methods and Results After the clinical diagnosis of BS had been established in a 35 years old male with identification of an SCN5A mutation, 59 family members were clinically and genetically evaluated and ECG recordings were performed with upward displacement of precordial leads. Conventional lead position confirmed BS diagnostic (type 1 Brugada ECG) in 2 patients (sensitivity 8,3% and specificity 88,6%). Positioning of the right precordial leads in the 2nd intercostal space augmented the sensitivity to 45,8% (p=0,002), with an inferior specificity (85,7%) (p=0,5). In the 1st intercostal space, the sensitivity increased to 54,2% (p=0,0005) with the smallest specificity (82,9%, p=0,25). Conclusion We concluded, with statistic significance, that modified upward positioning of right precordial leads augments ECG sensibility in BS diagnostic. The specificity of the exam lowers, but the difference isn’t statistically significant.