Sep.2-7,2006 Barcelona, Spain
Defining Criteria for the “Gradually Descending ST-segment Elevation” in Patients with Brugada Syndrome
Masahiko Takagi, M.D., Ph.D, Yasuhiro Yokoyama, M.D., Kazutaka Aonuma, M.D. ,Ph.D, Naohiko Aihara, M.D., and Masayasu Hiraoka, M.D.,Ph.D.,FAHA.,FACC. for the Japan Idiopathic Ventricular Fibrillation Study (J-IVFS) Investigators
A definition of the “gradually descending ST-segment elevation” in the right precordial leads (Wilde et al, Circulation,2002) in patient with coved-type (type 1) Brugada ECG is still unclear. The aim of the present study is to define the “gradually descending ST-segment elevation” in ECG, especially defining it from incomplete right bundle branch block (iRBBB).
We studied a total of 103 spontaneous type 1 Brugada ECG from 86 patients enrolled in the Japan Idiopathic Ventricular Fibrillation Study (J-IVFS) (Brugada group) and 86 iRBBB-type ECG with ST-segment elevation and negative T wave from 87 individuals (iRBBB group). The amplitudes of the peak of r’ wave (r’) and the ST-segment 40 and 80 msec after r’ (r’40 and r’80, respectively) were measured visually by 4 independent observers from all right precordial leads with coved-type ST-segment elevation or iRBBB-type ECG. We calculated the differences in amplitudes between r’ and r’40 (r’-r’40), r’40 and r’80 (r’40-r’80), and r’ and r’80 (r’-r’80) and the values between the 2 groups were compared.
In Brugada group, we found more gradually descending ST-T configuration just after r’ in Brugada group than in iRBBB group (0.09±0.07 and 0.45±0.24 mV [p<0.0001] for r’-r’40, 0.18±0.26 and 0.52±0.26 mV [p<0.0001] for r’-r’80, Brugada group v.s. iRBBB group, respectively). Our calculation suggested r’- r’40 was the most useful index in measured parameters to distinguish the 2 groups. The cut off value for the Brugada group as determined from the receiver operating characteristic curve was 0.18 mV in r’- r’40. Sensitivity and specificity were 97 and 91 %, respectively. Conclusions We defined the “gradually descending ST-segment elevation” in patients with type 1 ECG sign of Brugada syndrome as the parameter for r’- r’40 value under 0.18 mV. This parameter is considered useful to distinguish type 1 Brugada ECG from iRBBB-type ECG with ST-segment elevation and negative T wave.