Ventricular arrhythmias in Brugada syndrome (BrS) may be due to a combination of myocardial depolarization and repolarization abnormalities. The spatial QRS-T angle, measured by 3D ECG, reflects both myocardial depolarization and repolarization and has been proposed as a marker for sudden cardiac death risk in several cardiomyopathies. This marker has never been evaluated in BrS patients.

To evaluate the prognostic significance of the spatial QRS-T angle in patients with a spontaneous Brugada type 1 pattern (SBT1).

8 patients with a SBT1 were included (8 males, mean age 49.1±10.9 years-old), 4 experienced sudden cardiac arrest or documented ventricular fibrillation (SCA/VF) at mean age of 38.8±14.3 years-old. We analyzed conventional ECG and 3D ECG data using the CAVIAR method and compared data from VF/SCA group to other subjects.

The spatial angle between the onset of the QRS and the T-wave loop (ODIRangle) was significantly higher in the SCA/VF group (49.1±26.0 vs. 19.8±3.8, P=0.029). There was no significant difference between patients for conventional ECG measurements (PR interval 187.0±29.6ms in the SCA/VF group vs. 186.0±38.7ms, P=1, QRS duration 130.0±38.7ms vs. 106.5±12.5ms, P=0.30, corrected QT interval 471.8±8.4ms vs. 404.3±45.1ms, P=0.057, Tpeak–Tend interval 115.5±3.8 ms vs. 107.5±34.7 ms, P=1) (Figure 1).

The spatial angle between the onset of QRS and the T-wave loop appears to be significantly correlated with the risk of VF/SCD in BrS patients. A prospective study is needed to confirm these findings.