Class IC antiarrhythmic drugs such as pilsicainide and

Class IC antiarrhythmic drugs such as pilsicainide and propafenone have been used to terminate or prevent ATs, particularly atrial fibrillation [15–17]. Pilsicainide and propafenone in Japan, and ajmaline in Europe, are commonly used as first-line drugs for antiarrhythmic therapy [13]. We often encounter Brugada-type ECG changes after drug therapy in daily clinical practice, but no epidemiological data have been reported. In the present study, we assessed the prevalence of Brugada-type ECGs after administration of class IC antiarrhythmic drugs in patients with paroxysmal ATs but without any risk-stratifying factors for the syndrome, such as syncopal episodes or a familial history of sudden death. We found that corticotropin releasing factor 6.3% of all the patients had a significant ST-segment elevation and norepinephrine 1.4% of the patients showed a typical Brugada-type ECG form with a coved pattern after drug administration. The prevalence of Brugada-type ECGs showing a coved pattern in lead V1 or V2 among healthy populations ranges from 0.05% to 0.27% in Japan [21–24] and from 0% to 0.1% in foreign countries [18–20,25]. The prevalence of 1.4% in our study was at least 10-fold greater than the mean prevalence (0.1–0.2%) of Brugada-type ECGs in the healthy Japanese population. This may suggest that lone AT patients are more susceptible to Brugada syndrome than healthy subjects. In fact, 20–40% of patients with Brugada syndrome have also been reported to have ATs [26–28].
Conclusions
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