Characterization of repolarization in Brugada syndrome patients during exercise testing: Dynamic angle evaluation.

BACKGROUND: A new ECG criterion has been studied in Brugada syndrome (BrS) at rest to differentiate type 2 and incomplete right bundle branch block (IRBBB).

METHODS: We assessed this criterion during exercise comparing BrS (46 patients) and IRBBB (17 patients). A beta angle was measured from lead V1 between the upslope of S-wave and the downslope of the r'-wave.

RESULTS: Beta angle was significantly larger in BrS at rest (58±24° vs 25±15°, p<0.001), exercise (47±26° vs 15±11°, p<0.001), and recovery (46±24° vs 21±12°, p<0.001) with a reduction in angle at exercise compared to rest. There was a significant rebound in angle at recovery in the control group to (p<0.001); no such rebound was observed in the BrS group (p=NS).

CONCLUSION: Beta angle study at rest and its evolution at exercise could help discriminate BrS patients from healthy subjects.