BACKGROUND: The aim of study was to investigate effects of beta-blockade on microvolt T-wave alternans (TWA), a precursor of lethal arrhythmia, in patients with long QT syndrome (LQTS). METHODS: Eleven consecutive LQTS patients, types 1 (n = 6), 3 (n = 2), and "non-1, non-2, non-3" (n = 3) were enrolled. All patients underwent 24-hr continuous 12-lead ECG monitoring before and after initiation of beta-blockade therapy. TWA was measured using the modified moving average method. RESULTS: Seven (63.6%) of the 11 patients studied were symptomatic, with history of cardiac arrest or documented Torsade de Pointes (TdP) in 4 and syncope in three patients. After a median follow-up of 34 months, beta-blockade reduced the number of symptomatic patients to 1 with TdP (p < 0.02), in whom TdP frequency decreased from 25 events/60 months (0.42 event/month) to seven events/69 months (0.1 event/month). In association with this reduction in symptoms, peak TWA decreased by 47% in the cohort after a median of eight months of beta-blockade therapy [from 95 (74-130) to 50 (39.5-64.5) µV, p = 0.01]. All patients exhibited TWA ≥42 µV before beta-blockade therapy, which eliminated these episodes in four patients. Daily frequency of TWA ≥42 µV episodes decreased by 87% [from 15 (6-26) to 2 (0-5) episodes/day, p = 0.009]. CONCLUSIONS: This study is limited by the small sample size and is mainly hypothesis generating. TWA monitoring deserves further evaluation as a risk marker and a guide to therapy in LQTS patients in future large-scale studies.
BACKGROUND: The aim of study was to investigate effects of beta-blockade on microvolt T-wave alternans (TWA), a precursor of lethal arrhythmia, in patients with long QT syndrome (LQTS). METHODS: Eleven consecutive LQTS patients, types 1 (n = 6), 3 (n = 2), and "non-1, non-2, non-3" (n = 3) were enrolled. All patients underwent 24-hr continuous 12-lead ECG monitoring before and after initiation of beta-blockade therapy. TWA was measured using the modified moving average method. RESULTS: Seven (63.6%) of the 11 patients studied were symptomatic, with history of cardiac arrest or documented Torsade de Pointes (TdP) in 4 and syncope in three patients. After a median follow-up of 34 months, beta-blockade reduced the number of symptomatic patients to 1 with TdP (p < 0.02), in whom TdP frequency decreased from 25 events/60 months (0.42 event/month) to seven events/69 months (0.1 event/month). In association with this reduction in symptoms, peak TWA decreased by 47% in the cohort after a median of eight months of beta-blockade therapy [from 95 (74-130) to 50 (39.5-64.5) µV, p = 0.01]. All patients exhibited TWA ≥42 µV before beta-blockade therapy, which eliminated these episodes in four patients. Daily frequency of TWA ≥42 µV episodes decreased by 87% [from 15 (6-26) to 2 (0-5) episodes/day, p = 0.009]. CONCLUSIONS: This study is limited by the small sample size and is mainly hypothesis generating. TWA monitoring deserves further evaluation as a risk marker and a guide to therapy in LQTS patients in future large-scale studies.
Authors: Silvia G Priori; Arthur A Wilde; Minoru Horie; Yongkeun Cho; Elijah R Behr; Charles Berul; Nico Blom; Josep Brugada; Chern-En Chiang; Heikki Huikuri; Prince Kannankeril; Andrew Krahn; Antoine Leenhardt; Arthur Moss; Peter J Schwartz; Wataru Shimizu; Gordon Tomaselli; Cynthia Tracy Journal: Heart Rhythm Date: 2013-08-30 Impact factor: 6.343
Authors: Michael J Ackerman; Silvia G Priori; Anne M Dubin; Peter Kowey; Nicholas J Linker; David Slotwiner; John Triedman; George F Van Hare; Michael R Gold Journal: Heart Rhythm Date: 2016-09-19 Impact factor: 6.343
Authors: Eric J Rashba; Michael Cooklin; Karen MacMurdy; Neal Kavesh; Malcolm Kirk; Samantha Sarang; Robert W Peters; Stephen R Shorofsky; Michael R Gold Journal: Circulation Date: 2002-02-19 Impact factor: 29.690
Authors: G Michael Vincent; Peter J Schwartz; Isabelle Denjoy; Heikki Swan; Candice Bithell; Carla Spazzolini; Lia Crotti; Kirsi Piippo; Jean-Marc Lupoglazoff; Elizabeth Villain; Silvia G Priori; Carlo Napolitano; Li Zhang Journal: Circulation Date: 2008-12-31 Impact factor: 29.690