Spatial QRS-T angle: A new risk marker for sudden cardiac arrest in Brugada syndrome?

Abstract

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 (ODIR angle) 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 ± 29.6 ms in the SCA/VF group vs. 186.0 ± 38.7 ms, P = 1, QRS duration 130.0 ± 38.7 ms vs. 106.5 ± 12.5 ms, P = 0.30, corrected QT interval 471.8 ± 8.4 ms vs. 404.3 ± 45.1 ms, P = 0.057, Tpeak–Tend interval 115.5 ± 3.8 ms vs. 107.5 ± 34.7 ms, P = 1) ( Fig. 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.