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Type: Journal article
Title: T wave amplitude correction of QT interval variability for improved repolarization lability measurement
Author: Schmidt, M.
Baumert, M.
Malberg, H.
Zaunseder, S.
Citation: Frontiers in Physiology, 2016; 7(JUN):216-1-216-8
Publisher: Frontiers Media SA
Issue Date: 2016
ISSN: 1664-042X
Statement of
Martin Schmidt, Mathias Baumert, Hagen Malberg and Sebastian Zaunseder
Abstract: The inverse relationship between QT interval variability (QTV) and T wave amplitude potentially confounds QT variability assessment. We quantified the influence of the T wave amplitude on QTV in a comprehensive dataset and devised a correction formula.Three ECG datasets of healthy subjects were analyzed to model the relationship between T wave amplitude and QTV. To derive a generally valid correction formula, linear regression analysis was used. The proposed correction formula was applied to patients enrolled in the Evaluation of Defibrillator in Non-Ischemic Cardiomyopathy Treatment Evaluation trial (DEFINITE) to assess the prognostic significance of QTV for all-cause mortality in patients with non-ischemic dilated cardiomyopathy.A strong inverse relationship between T wave amplitude and QTV was demonstrated, both in healthy subjects (R² = 0.68, p < 0.001) and DEFINITE patients (R² = 0.20, p < 0.001). Applying the T wave amplitude correction to QTV achieved 2.5-times better group discrimination between patients enrolled in the DEFINITE study and healthy subjects. Kaplan-Meier estimator analysis showed that T wave amplitude corrected QTVi is inversely related to survival (p < 0.01) and a significant predictor of all-cause mortality.We have proposed a simple correction formula for improved QTV assessment. Using this correction, predictive value of QTV for all-cause mortality in patients with non-ischemic cardiomyopathy has been demonstrated.
Keywords: ECG; QT interval variability; T wave amplitude; risk stratification; DEFINITE
Rights: Copyright © 2016 Schmidt, Baumert, Malberg and Zaunseder. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
DOI: 10.3389/fphys.2016.00216
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Electrical and Electronic Engineering publications

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