1 Cardiology Division, Hospital de Clínicas de Porto Alegre, Porto Alegre 90035-903, Brazil. Electronic address: [email protected].
2 Duke University Medical Center, Duke Clinical Research Institute, Durham, NC, USA.
3 Harvard-Thorndike Electrophysiology Institute, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
4 Cardiology Division, Hospital de Clínicas de Porto Alegre, Porto Alegre 90035-903, Brazil; Cardiology Division, Hospital Moinhos de Vento, Porto Alegre, Brazil.