Brugada Syndrome with Early Repolarization masked by Complete Right Bundle-Branch Block: Figure 1

We have read with great interest the case presented by Dr Ito et al.1 about the giant negative T-wave with J-wave augmentation on 12-lead electrocardiography (ECG) associated with sudden cardiac death (SCD). We want to address some points that merit more attention. Although the early repolarization (ER) has been accepted as a benign ECG variant for decades; recent studies have confirmed that ER with J waves is associated with idiopathic ventricular fibrillation. Due to the high prevalence of an ER pattern in the general population and a low ventricular fibrillation event rate, it remains challenging to differentiate a malignant ER syndrome (ERS) from a benign form, and also from a Brugada syndrome (BrS).2,3 In both arrhythmic syndromes, ST-segment elevation with J-wave augmentation is usually observed as a result of transmural voltage gradient, and contemporary data have shown a peak incidence of SCD in both syndromes at mid-night and early morning.4 A high prevalence of ER has also been found in a subgroup of patients with BrS associated with ES,3 and reported that the prognosis of BrS with ES significantly worse than that of patients without ES.3 Recently, Hu et al.2 revealed that a gain of function in one subunit of the ATP-sensitive K(+) channel when coupled with a loss of function in SCN5A may underlie Type 3 ERS, which is associated with a severe arrhythmic phenotype. Therefore, in clinic practice, there may be cases where the dividing line is not so clear.4 Indeed, Brugada and Brugada initially described a right bundle branch block (RBBB) pattern among their eight cases of BrS. Thereafter, it was shown that, whereas the presence of the RBBB pattern is not necessary in reaching a diagnosis of BrS, it is supportive. However, the characteristic ECG of BrS can be masked by complete RBBB and exposed by resolution of the block or pharmacological or pacing manoeuvers.5 Recently we had a Brs patient obscured by complete RBBB (Figure 1). Investigation of his family history found that his uncle and grandfather were diagnosed as BrS because of frequent syncopal attacks, and his uncle had recently undergone insertion of an ICD because of his frequent syncopal attacks. He had a history of surgery for ventricular septal defect closure by the age of 1. His complete RBBB makes the diagnosis of BrS very difficult from ECG locating the fourth intercostal space (Figure 1), as it could be suspected only in lead V2 (arrow in Figure 1B) due to the marked abnormal ST-segment elevation taken from the second intercostal space. Thus, a BrS should be ruled out whenever a slight ST-segment elevation is observed in right precordial leads in the presence of an RBBB.5 (A) 12 lead electrocardiogram fourth intercostal space shows complete RBBB. (B) 12 lead electrocardiogram second intercostal space shows complete RBBB with marked ST-segment elevation in V2 (arrow). A careful examination of ECG reported by authors1 shows Type-2 Brugada pattern in Figure 1C, and a slight ST-segment elevation with a RBBB-like pattern in V2 (Figure 1A). Since placing the right precordial ECG leads at an upper position (second or third intercostal spaces) increases the sensitivity of ECG to detect all types of the BrS, it would be nice to take an ECG at the upper (second intercostal) space and perform an ajmaline testing to differentiate the ERS from BrS.1 It might also unmask the true RBBB. These manoeuvers may provide us a clue for Brs with or without ERS, or vice versa. We would like to thank authors for this instructional case presentation. Conflicts of interest: There is no relationship with industry.