Diagnosis of non-type I Brugada syndrome patients by vectorcardiographic measurements

Brugada syndrome (BrS) causes sudden death in patients with structurally normal hearts. Manifestation of BrS in the ECG is dynamic and most patients do not show unequivocal signs of the syndrome during ECG screening. We studied the vectorcardiograms (VCG) of 98 BrS patients, 61 of whom did not present type I ECG at the time of the recording and 59 control subjects. The orientation and duration of terminal R waves present in -X and/or -Y orthogonal leads were measured. Terminal R waves were present in 85% BrS patients without a type I ECG, 53% of control subjects and 96% of RBBB patients. Terminal R waves of BrS patients were longer than those of healthy subjects. Orientation of terminal R waves of BrS patients and healthy subjects was similar, but differed in RBBB patients. Identification of BrS patients without a type I ECG can be highly improved by measuring the duration and orientation of terminal R waves.