Clinical characterization and pedigree of the proband.

<p><b>A</b>. ECG of the proband at hospital admission with an episode of ventricular fibrillation initiated by a premature ventricular contraction (paper speed 25 mm/s). Reprinted from [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0081493#B21" target="_blank">21</a>] under a CC BY license, with permission from Elsevier original copyright (2011). <b>B</b>. 12-Lead ECG of the proband after flecainide continuous infusion at 2 mg/kg for 10 min (paper speed 25 mm/s). <b>C</b>. Pedigree of the affected family. Circles and squares represent female and male subjects, respectively. White and black symbols represent unaffected and affected individuals, respectively. The arrow denotes the proband. Diagonal lines indicate deceased subjects. The asterisk denotes proband`s relatives subjected to genetic and electrophysiological analyses (including flecainide test). Patient named in the figure as III.4 was excluded from the pharmacological test and ECG analysis because she had suffered Tetrallogy of Fallot that had been corrected in childhood, although she is a mutation carrier. <sup><i>δ</i></sup> denotes proband`s relatives who displayed type 1 BrS pattern after flecainide challenge. <b>D</b>. ECG of the proband´s son (top) and sister (bottom) after flecainide challenge.