Sensitivity and specificity of sodium channel blocking test in the diagnosis of Brugada syndrome.

The ECG features of Brugada syndrome are dynamic and frequently concealed. Sodium channels blockers are widely used to unmask the Brugada electrocardiographic (ECG) pattern. The sensitivity and specificity of I(Na) channel blocking test varies significantly. A negative I(Na) blocking test does not exclude the presence of a SCN5A mutation, which is responsible for the phenotype of Brugada syndrome. Herein, we describe the case of a 65-years-old asymptomatic male who underwent a I(Na) channel blocking test, seven years ago due to a type 2 ECG pattern (saddleback configuration) which failed to induce the diagnostic type 1 ECG pattern. Diagnostic considerations at a molecular level and their clinical relevance are being discussed. Copyright 2008 Elsevier Ireland Ltd. All rights reserved.