New ECG Criteria for High-Risk Brugada Syndrome

Hirotsugu Atarashi, Satoshi Ogawa, for the Idiopathic Ventricular Fibr
2003 Circulation Journal  
ince Brugada and Brugada 1 reported a unique electrocardiographic syndrome that is predominantly diagnosed in males and often associated with ventricular fibrillation (VF), much attention has been paid to the detection of a right bundle branch block pattern associated with bizarre ST elevation in the right precordial leads (V1-3). In clinical practice, it is very important to identify patients who have a high risk of developing VF and sudden death, and for this purpose, ST elevation in the
more » ... evation in the precordial leads is not very useful because it varies in shape and amplitude day by day 2 and is also dependent on electrode positioning. 3 We have investigated the prevalence of Brugada syndrome in the working Japanese population, and our 3-year follow-up data demonstrated a very low cardiac event rate in asymptomatic patients. 4 On the other hand, symptomatic patients often need an implantable cardioverter defibrillator (ICD) because of a high incidence of recurrence. 5,6 Recent reports 7,8 have suggested an important contribution of intraventricular conduction delay to the onset of lethal ventricular arrhythmias and so we hypothesized that there might be some findings on the standard 12lead electrocardiogram (ECG) reflecting intraventricular conduction delay that could be used to distinguish highand low-risk patients. In order to clarify the ECG characteristics that could be useful for the diagnosis of high-risk Brugada syndrome, we reviewed 12-lead ECGs from the Japanese Brugada syndrome registry. Methods We reviewed standard 12-lead ECGs that were on file at the Japanese Brugada syndrome registry 2,4 and selected 60 from 60 patients because their quality was sufficient for accurate measurement of the QRS width and ST amplitude in the right precordial leads. All ECGs were recorded at a paper speed of 25 mm/s. The ECGs were from 17 patients with a history of VF, 9 patients with episodes of syncope, and 34 asymptomatic patients (Table 1) . We measured the width of the S wave and ST segment elevation in leads V1 and V2 because there is usually a prominent r' in Brugada syndrome and either of these 2 leads shows the maximum ST segment elevation. We thought that conduction delay might be detected at the terminal portion of the QRS deflection, so the S wave of V1 and V2 was measured from the tip of r to the tip of r', and the amplitude of the ST segment was measured at 0.08 s from the J point. These measurement were made by 2 cardiologist who were unaware of the clinical information about the patients. Magnification was used to minimize the measuring error. When the measured values were not identical, the mean value of the 2 measurements was calculated. Data Analysis All variables are reported as the mean ± SD for each group. The nonparametric Mann-Whitney U test was used to assess the significance of differences between the groups. Correlations between the presence or absence of for the Idiopathic Ventricular Fibrillation Investigators To identify high-risk patients with Brugada syndrome, the present study reviewed 60 standard 12-lead electrocardiograms from 60 patients collected by the Japanese Brugada syndrome registry. Under blinded conditions, the S wave of lead V1 was measured from the tip of r to r', and the amplitude of the ST segment in lead V2 was measured at 0.08 s from the J point. In patients with ventricular fibrillation (n=17), the S wave was significantly longer in V1 (0.085±0.007 s vs 0.075±0.011 s, p=0.001), and ST segment elevation in V2 was significantly greater (0.323±0.133 mV vs 0.236±0.129 mV, p=0.012) than in patients without fibrillation. An S wave width of 0.08 s or more in V1 had a positive predictive value of 40.5% and negative predictive value of 100% for ventricular fibrillation, with 100% sensitivity. ST elevation of 0.18 mV or more in V2 had a positive predictive value of 37.8% and a negative predictive value of 100% for ventricular fibrillation, with 100% sensitivity. Both an S wave width ≥0.08 s in V1 and ST elevation ≥0.18 mV in V2 were highly specific indicators of ventricular fibrillation and are proposed as new criteria for high-risk Brugada syndrome. (Circ J 2003; 67: 8 -10)
doi:10.1253/circj.67.8 pmid:12520143 fatcat:atgbh2qborabzk5t3m4zd77khe