Abstract 2686: Diagnostic Utility of Bipolar Precordial Leads During Ajmaline Testing for Suspected Brugada Syndrome
Background: In order to increase the sensitivity of the standard 12-lead electrocardiogram (ECG) to diagnose Brugada syndrome (BS) we tested the hypothesis that a bipolar precordial lead with a positive electrode at V2 and a negative electrode at V4 or V5 is more sensitive than lead V2 for detection of type 1 Brugada ECG pattern.
Methods: We analysed a database of 15-lead ECGs (standard 12 leads + V1 to V3 one intercostal space higher, i.e. V1h, V2h, V3h) collected during ajmaline test in 128 patients (80 males, age 37 +− 15 years, 48 females, age 39 +− 15 years). Bipolar leads between V2 (positive pole) and V4 or V5 (leads V2– 4, V2–5) were derived by subtracting leads V4 and V5 respectively from V2. The test was considered positive when type 1 pattern was present in any 2 of the 6 leads V1 to V3, V1h to V3h.
Results: There were 21 (16.4%) positive tests. Type 1 pattern was observed in 20 positive tests in lead V2h, but only in 10 tests in V2. In 7 positive tests, in which lead V2h but not V2 displayed type 1 Brugada pattern, lead V2– 4 and/or V2–5 showed type 1 pattern. Substituting lead V2 with leads V2– 4/V2–5 would increase the ability of leads V1, V2 and V3 to detect a positive test from 33.3% (7/21) to 42.9% (9/21). Type 1 pattern was observed in V2– 4 or V2–5 during 2 non-positive tests (false-positive result). Figure⇓: ECGs recorded at baseline (left) and 6 min after start of ajmaline right) during a positive test. Lead V2h, V2– 4 and V2–5 show type 1 pattern, whereas lead V2 shows non-diagnostic type 2 pattern.
Conclusion: The use of a bipolar precordial lead V2– 4/V2–5 instead of V2 increases the sensitivity for detecting diagnostic type 1 Brugada pattern by 9.6%, at the expense of a small reduction in specificity of 1.9%.