LAUSR

DOI: 10.5935/abc.20180081 Visible T-wave alternans (TWA) has been reported since 1909, being, thus, not a recent finding.1 However, non-visible and far less rare microvolt TWA has gained importance because of its association with electrical disorders and the high risk for sudden cardiac death (SCD) or arrhythmic events,2-6 being assessed in several clinical trials and population studies, such as TWA in HF,7 ALPHA Study,8 REFINE Study,9 FINCAVAS,10 the collaborative study by Ikeda et al.11 and the MADIT-II-type research by Bloomfield et al.12 All those studies have in common the fact that they evidence the high negative predictive value of TWA regarding SCD or arrhythmic events, with low to intermediate positive predictive value.