Takasugi N, et al. - In 11 consecutive long QT syndrome (LQTS) patients, researchers determined the impacts of beta-blockade on microvolt T-wave alternans (TWA), a precursor of lethal arrhythmia. This study included types 1 (n = 6), 3 (n = 2), and “non-1, non-2, non-3” (n = 3) patients, who were assessed using 24-hr continuous 12-lead ECG monitoring before and after initiation of beta-blockade therapy. Using the modified moving average method, TWA was measured. Symptomatic subjects were 7 (63.6%), with history of cardiac arrest or documented Torsade de Pointes (TdP) in 4 and syncope in three patients. Participants were examined during a median follow-up of 34 months. Findings revealed beta-blockade attenuated the number of symptomatic patients to 1 with TdP, in whom TdP frequency reduced from 25 events/60 months (0.42 event/month) to seven events/69 months (0.1 event/month). After a median of eight months of beta-blockade therapy, they noted peak TWA decreased by 47% in association with this reduction in symptoms. Prior to beta-blockade therapy, TWA ≥42 µV was shown by all patients, which eliminated these episodes in 4 patients. They also noted daily frequency of TWA ≥42 µV episodes decreased by 87% [from 15 (6–26) to 2 (0–5) episodes/day].