BACKGROUND: Increased spatial and temporal dispersion of repolarization contributes to ventricular arrhythmogenesis. Beat-to-beat fluctuations in T-wave timing are thought to represent such dispersion and may predict clinical events. OBJECTIVE: The purpose of this study was to assess whether a novel noninvasive measure of beat-to-beat instability in T-wave timing would provide additive prognostic information in post-myocardial infarction patients. METHODS: We studied 678 patients from 12 hospitals with 32-lead 5-minute electrocardiogram recordings 6-8 weeks after myocardial infarction. Custom software identified R wave-to-T wave intervals (RTIs) and diastolic intervals (DIs). Repolarization scatter (RTI:DI(StdErr)) was then calculated as the standard error about the RTI:DI regression line. In addition, left ventricular ejection fraction (LVEF), short-term heart rate variability (HRV) parameters, and QT variability index were measured. Patients were followed for the composite endpoint of death or life-threatening ventricular arrhythmia. RESULTS: After a mean follow-up of 63 months, 134 patients met the composite endpoint. An RTI:DI(StdErr) >5.50 ms was associated with a 210% increase in arrhythmias or deaths (P <.001). After adjusting for LVEF, RTI:DI(StdErr) remained an independent predictor (P <.001). RTI:DI(StdErr) was also independent of short-term HRV parameters and the QT variability index. CONCLUSIONS: Increased repolarization scatter, a measure of high-frequency, cycle-length-dependent repolarization instability, predicts poor outcomes in patients after myocardial infarction.
BACKGROUND: Increased spatial and temporal dispersion of repolarization contributes to ventricular arrhythmogenesis. Beat-to-beat fluctuations in T-wave timing are thought to represent such dispersion and may predict clinical events. OBJECTIVE: The purpose of this study was to assess whether a novel noninvasive measure of beat-to-beat instability in T-wave timing would provide additive prognostic information in post-myocardial infarctionpatients. METHODS: We studied 678 patients from 12 hospitals with 32-lead 5-minute electrocardiogram recordings 6-8 weeks after myocardial infarction. Custom software identified R wave-to-T wave intervals (RTIs) and diastolic intervals (DIs). Repolarization scatter (RTI:DI(StdErr)) was then calculated as the standard error about the RTI:DI regression line. In addition, left ventricular ejection fraction (LVEF), short-term heart rate variability (HRV) parameters, and QT variability index were measured. Patients were followed for the composite endpoint of death or life-threatening ventricular arrhythmia. RESULTS: After a mean follow-up of 63 months, 134 patients met the composite endpoint. An RTI:DI(StdErr) >5.50 ms was associated with a 210% increase in arrhythmias or deaths (P <.001). After adjusting for LVEF, RTI:DI(StdErr) remained an independent predictor (P <.001). RTI:DI(StdErr) was also independent of short-term HRV parameters and the QT variability index. CONCLUSIONS: Increased repolarization scatter, a measure of high-frequency, cycle-length-dependent repolarization instability, predicts poor outcomes in patients after myocardial infarction.
Authors: Vijay S Chauhan; Eugene Downar; Kumaraswamy Nanthakumar; John D Parker; Heather J Ross; Wilson Chan; Peter Picton Journal: Am J Physiol Heart Circ Physiol Date: 2005-08-19 Impact factor: 4.733
Authors: J M Cao; L S Chen; B H KenKnight; T Ohara; M H Lee; J Tsai; W W Lai; H S Karagueuzian; P L Wolf; M C Fishbein; P S Chen Journal: Circ Res Date: 2000-04-14 Impact factor: 17.367
Authors: Larisa G Tereshchenko; Lichy Han; Alan Cheng; Joseph E Marine; David D Spragg; Sunil Sinha; Darshan Dalal; Hugh Calkins; Gordon F Tomaselli; Ronald D Berger Journal: Heart Rhythm Date: 2010-09-29 Impact factor: 6.343
Authors: Mathias Baumert; Alberto Porta; Marc A Vos; Marek Malik; Jean-Philippe Couderc; Pablo Laguna; Gianfranco Piccirillo; Godfrey L Smith; Larisa G Tereshchenko; Paul G A Volders Journal: Europace Date: 2016-01-27 Impact factor: 5.214
Authors: Robert L Lux; Christopher Todd Sower; Nancy Allen; Susan P Etheridge; Martin Tristani-Firouzi; Elizabeth V Saarel Journal: PLoS One Date: 2014-01-15 Impact factor: 3.240