Pilsicainide Administration Unmasks a Phenotype of Brugada Syndrome in a Patient with Overlap Syndrome due to the E1784K SCN5A Mutation

Figures

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  Figure 1.. Findings of the 12-lead electrocardiogram at rest (A, B), chest X-ray, and transthoracic echocardiogram (C). The electrocardiogram shows sinus rhythm, QT prolongation (QT interval: 514 ms, QTc interval: 485 ms), and mild saddleback-type ST elevation (A). Coved-type ST elevation is not observed, even in the second and third intercostal spaces (B). The chest X-ray and transthoracic echocardiogram findings are essentially normal (C). HR: heart rate

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  Figure 2.. Isoproterenol administration test (A) and mexiletine administration test (B). Continuous infusion of isoproterenol does not induce paradoxical QT prolongation (A). Mexiletine 2.5 mg/kg administration shortens the QT interval by 40 ms and does not change the saddleback-type ST elevation, even in the second and third intercostal spaces (B). ISP: isoproterenol, γ: μg/kg/min

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  Figure 3.. Pilsicainide administration test. Pilsicainide administration at 1 mg/kg induces coved-type ST elevation in leads V1-3 and prolongs QRS duration from 96 to 158 ms and the PQ interval from 184 to 248 ms (A). Shortly after the appearance of coved-type ST elevation, a premature ventricular contraction induces VF (B). The coved-type ST elevation is reversed by continuous isoproterenol infusion (C).

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  Figure 4.. The family pedigree (A) and 12-lead electrocardiogram findings of the patient’s elder sister (B) and niece (C). The patient is indicated by an arrow (A). The electrocardiogram of the patient’s elder sister shows normal findings (B). The electrocardiogram of the patient’s niece shows QT prolongation (C).