Abstract
Prevalence of microvolt T-wave alternans (TWA) and the strength of its association with torsade de pointes (TdP) history have not been fully investigated in patients with long QT syndrome (LQTS). Twenty-four-hour continuous 12-lead ECGs were recorded in 10 healthy subjects (5 men; median age, 21.5 years) and 32 patients (13 men; median age, 13 years) with LQTS types 1 (n=18), 2 (n=4), 3 (n=4), and unidentified (n=6). Peak TWA was determined by the Modified Moving Average method. None of the healthy subjects had TWA ≥42 µV. All 8 (100%) LQTS patients with a history of TdP exhibited TWA ≥42 µV, whereas only 14 (58.3%) of the 24 LQTS patients without TdP history reached ≥42 µV (p=0.04). Thus, the 42-µV cut point provided 100% sensitivity and 41.7% specificity for an association with TdP history. In the 22 (68.8%) LQTS patients with TWA ≥42 µV, only 2 (median; interquartile range, 1-3) leads exhibited TWA ≥42 µV. Highest TWA levels were recorded in precordial leads (V1-V6) in 30 (93.8%) patients, most frequently in lead V2 (43.8%). A single ECG lead detected only ≤63.6% of TWA ≥42 µV episodes, whereas the combined leads V2 to V5 detected 100% of TWA ≥42 µV. Microvolt TWA is far more prevalent in LQTS patients than previously report...Continue Reading
References
Jan 1, 1975·American Heart Journal·P J Schwartz, A Malliani
Nov 1, 1991·Journal of the American College of Cardiology·M B Rosenbaum, R S Acunzo
Sep 1, 1994·Cardiovascular Research·B D NearingR L Verrier
Jun 1, 1994·Journal of the American College of Cardiology·W ZarebaW J Hall
Mar 1, 1996·Pediatric Cardiology·C J MacheJ I Stein
Mar 23, 2000·The American Journal of Cardiology·R H AliA Medina
Jul 18, 2000·Journal of the American College of Cardiology·F E Cruz FilhoJ C Ribeiro
May 3, 2001·Journal of Cardiovascular Electrophysiology·E S KaufmanA M Brown
Dec 12, 2001·Journal of the American College of Cardiology·T KlingenhebenS H Hohnloser
Jan 18, 2002·Journal of Applied Physiology·Bruce D Nearing, Richard L Verrier
Jul 25, 2003·Pacing and Clinical Electrophysiology : PACE·Jan NemecWin-Kuang Shen
Nov 3, 2004·Circulation·Marcin GrabowskiGrzegorz Opolski
Feb 22, 2005·Journal of Cardiovascular Electrophysiology·Mitsuhiro NishizakiMasayasu Hiraoka
Apr 11, 2006·IEEE Transactions on Bio-medical Engineering·Juan Pablo MartínezPablo Laguna
Oct 3, 2006·Journal of the American College of Cardiology·Elizabeth S KaufmanJ Thomas Bigger
Aug 5, 2009·Circulation·Christopher L Holley, Jonas A Cooper
Oct 7, 2009·Annals of Noninvasive Electrocardiology : the Official Journal of the International Society for Holter and Noninvasive Electrocardiology, Inc·Jörn SchmittJoachim R Ehrlich
Nov 9, 2010·Heart Rhythm : the Official Journal of the Heart Rhythm Society·Johanna LeinoTuomo Nieminen
Feb 15, 2011·Europace : European Pacing, Arrhythmias, and Cardiac Electrophysiology : Journal of the Working Groups on Cardiac Pacing, Arrhythmias, and Cardiac Cellular Electrophysiology of the European Society of Cardiology·Nobuhiro TakasugiShinya Minatoguchi
Sep 17, 2011·Journal of the American College of Cardiology·Richard L VerrierDavid S Rosenbaum
Mar 6, 2012·Europace : European Pacing, Arrhythmias, and Cardiac Electrophysiology : Journal of the Working Groups on Cardiac Pacing, Arrhythmias, and Cardiac Cellular Electrophysiology of the European Society of Cardiology·Tomonori KawaguchiRichard L Verrier
May 2, 2013·Journal of Cardiovascular Electrophysiology·Hiroko GotoTakashi Kuwahara
Sep 10, 2013·Heart Rhythm : the Official Journal of the Heart Rhythm Society·Silvia G PrioriCynthia Tracy
Jan 5, 2014·Journal of Cardiovascular Electrophysiology·Hiroko GotoRichard L Verrier
Apr 26, 2014·Journal of Cardiovascular Electrophysiology·Yuko Uchimura-MakitaYasuki Kihara
Citations
Feb 4, 2016·Circulation. Arrhythmia and Electrophysiology·Andrew M Davis
Sep 13, 2017·Scientific Reports·Karan R ChaddaKamalan Jeevaratnam
Sep 4, 2019·Neurology·Trudy D PangRichard L Verrier
May 23, 2019·Arrhythmia & Electrophysiology Review·Nabil El-SherifMohamed Boutjdir
Jul 1, 2020·Cardiology in the Young·Liu Hsin-MingChiu Shuenn-Nan
Sep 21, 2018·Frontiers in Physiology·Gary TseWilliam K K Wu
Jan 1, 2016·Europace : European Pacing, Arrhythmias, and Cardiac Electrophysiology : Journal of the Working Groups on Cardiac Pacing, Arrhythmias, and Cardiac Cellular Electrophysiology of the European Society of Cardiology·Joanna LewekIwona Cygankiewicz
Dec 20, 2017·Journal of Arrhythmia·Yukiko Nakano, Shimizu Wataru
Feb 7, 2018·Pacing and Clinical Electrophysiology : PACE·Nabil El-SherifMohamed Boutjdir
Feb 8, 2019·Annals of Noninvasive Electrocardiology : the Official Journal of the International Society for Holter and Noninvasive Electrocardiology, Inc·Nobuhiro TakasugiRichard L Verrier
Jun 27, 2019·Annals of Noninvasive Electrocardiology : the Official Journal of the International Society for Holter and Noninvasive Electrocardiology, Inc·Nobuhiro TakasugiRichard L Verrier
Nov 28, 2017·Cardiac Electrophysiology Clinics·Andrés Ricardo Pérez-RieraMohammad Shenasa