A cardiac sodium channel mutation identified in Brugada syndrome associated with atrial standstill

Abstract
Takehara N, Makita N, Kawabe J, Sato N, Kawamura Y, Kitabatake A, Kikuchi K (Asahikawa Medical College, Asahikawa; Hokkaido University Graduate School of Medicine, Sapporo, Japan; and Cardiovascular Research Institute, Newark, NY, USA). A cardiac sodium channel mutation identified in Brugada syndrome associated with atrial standstill (Case Report). J Intern Med 2004; 255: 137–142. Mutations in the cardiac Na+ channel gene SCN5A are responsible for multiple lethal ventricular arrhythmias including Brugada syndrome and congenital long QT syndrome. Here we report a case of Brugada syndrome with ST elevation in the right precordial and inferior leads accompanied by atrial standstill and spontaneous ventricular fibrillation. Atrial standstill and J wave elevation were provoked by procainamide. Genetic analysis revealed a missense mutation (R367H) in SCN5A. The resultant mutant Na+ channel was nonfunctional when expressed heterologously in Xenopus oocytes. Our study suggests that genetic defects in SCN5A may be associated with atrial standstill in combination with ventricular arrhythmias.