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  • It is possible that this

    2019-05-06

    It is possible that this contradiction may be due to referral bias in the studies of Brugada et al. [20,21]. Second, it is possible that time of day influences the results of PES. The magnitude of ST-segment elevation in the right precordial leads in BS varies spontaneously over days and during the same day [22,23]. Usually, the time of maximal ST-segment elevation is during the night. The time when PES is performed does not generally coincide with the time of maximal ST-segment elevation. Because the degree of ST-segment elevation is associated with the arrhythmogenic substrate in BS, it is reasonable to assume that the rate of inducibility of VF or VT by PES will be higher if PES is performed at the time of maximal ST-segment elevation. Third, it is still very unclear whether asymptomatic individuals with Brugada ECG should undergo PES [20,21]. One potentially important reason for the divergent results in asymptomatic individuals is the relatively low rate of spontaneous cardiac events in all previous series other than the studies by Brugada et al. Even in asymptomatic individuals with spontaneous type 1 ECG, the rates of cardiac events in most published series are between 0% and 2.8% (mean follow-up of approximately 3.5 years). The number of asymptomatic individuals with cardiac events during follow-up was still too small to evaluate predictors of cardiac events, including PES. Further study is needed to improve the understanding of predictors of cardiac events in asymptomatic individuals with BS. In conclusion, most previous studies and 2 meta-analyses have provided evidence of the poor utility of PES for risk bcrp inhibitor in BS. However, there is still no unequivocal explanation for the discrepant results with regard to the role of PES for risk stratification. The limits of conventional PES should encourage investigative efforts to identify a new PES approach. At least, we should not use the stimulation protocol that was used in the PRELUDE registry for risk stratification in patients without documented VF. According to recent studies, a combined clinical and electrophysiologic approach or stimulation protocol consisting of a basic drive cycle of 500ms and up to 2 extrastmuli may be useful for risk profiling in BS. Further studies are warranted to evaluate the usefulness of the new PES protocol for risk stratification, especially in asymptomatic individuals with BS.
    Conflict of interest
    Introduction Twenty years have passed since the first report on Brugada syndrome [1]. The interesting electrocardiogram (ECG) characteristics of this syndrome have attracted the attention of many physicians and researchers, and almost 2000 reports on Brugada syndrome have been published. Symptomatic patients who have had a previous episode of aborted cardiac arrest (ACA) and syncope are at high risk for recurrent ventricular tachyarrhythmias. Previous studies that evaluated the long-term prognosis of Brugada syndrome patients have shown that a previous episode of ACA and syncope are high-risk markers [1–5]. Some studies have also shown various clinical risk factors for identifying high-risk patients (Table 1). Most of the observations from which risk factors for ventricular fibrillation (VF) were identified were carried out in patients who experienced cardiac arrest or VF, and it is still not clear whether these risk factors can identify high-risk patients among those in whom VF has not been documented.
    Clinical characteristics and prognosis
    Repolarization abnormality and prognosis
    Depolarization abnormality and prognosis
    Other indices
    Summary and proposed risk stratification The decision to implant an ICD in asymptomatic patients may be made by VF induction with a single or double extrastimuli in addition to the presence of spontaneous type 1 ECG [77]. The indication for an EPS is determined by the existence of ECG changes, including fQRS, inferolateral ER, and exercise-induced ST augmentation. If patients have one of these ECG findings, an EPS is recommended.