Session S64.1

Automatic Assessment of Right Ventricular Repolarisation Heterogeneity during Diagnostic Ajmaline Test for Suspected Brugada Syndrome

VN Batchvarov, II Christov, G Bortolan*, M Govindan, ER Behr

Institute of Biomedical Engineering
Padova, Italy

Background: The electrophysiological substrate of Brugada syndrome (BS) is abnormally increased transmural and regional epicardial dispersion of right ventricular (RV) repolarisation. Hence, quantitative assessment of RV repolarization dispersion may help to diagnose BS. We applied principal components analysis (PCA) to automatically quantify repolarization dispersion during diagnostic ajmaline test for suspected BS.
Methods: Digital 10-second 15-lead electrocardiograms (ECG) (500 Hz, 4.88 µV resolution, 12 standard leads + leads V1, V2 and V3 recorded 1 intercostal space higher, V1h to V3h) were acquired in 61 patients with suspected BS and visibly non-diagnostic ECGs (38 men, age 39±17 years) before, during and after i.v. administration of ajmaline (1 mg/kg for 5 minutes). PCA was performed on a beat-to-beat basis on automatically delineated J-T-end intervals using 3 sets of leads: a) V1, V2 and V3 (PCA_stand), b) V1h, V2h and V3h (PCA_high), and c) V1, V2, V3 plus V1h, V2h and V3h (PCA_total). PCA (ratio of 2nd to 1st eigenvalue) was expressed as mean (PCA(mean)) and maximum (PCA(max)) PCA of all complexes within a 10-s ECG.
Results: There were 20 patients with positive tests (57% male, age 42±16 years) and 41 with negative tests (63% male, age 38±17 years). Patients with positive tests had significantly higher PCA_high and PCA_total, but not PCA_stand on the pre-test ECG compared to those with negative tests (e.g. PCA(mean)_high: 0.124±0.13 vs 0.057±0.064, p=0.0099, PCA(max)_high: 0.147±0.15 vs 0.074±0.084, p=0.017). Following ajmaline, PCA increased significantly in both groups; however, the maximum drug-induced increase of PCA was highly significantly greater in patients with positive tests (PCA_stand: 2193±3170% vs 168±420%, p=0.0002, PCA_high:6406±12622% vs 192±350%, p=0.0039, PCA_total 3109±4196% vs 137±323%, p=0.000043, in patients with positive and negative tests, respectively).
Conclusions: Patients with BS and visibly non-diagnostic resting ECG seem to have increased RV repolarisation dispersion. PCA can potentially improve the interpretation of the ajmaline test and facilitate the diagnosis of BS.

(Abstract Control Number: 33)