The Relation of QT Dispersion and Localized QT Difference to Coronary Pathology in a Population with Unstable Coronary Artery Disease
Methods: The 276 patients were recruited from the FRISC II trial. As the QTd parameter we used the mean value of automatically measured QTd during 27 hours after admission (QTdMean). As a local repolarization measure we used the maximal difference in QT between two adjacent ECG leads (QTdiffMean). The computations were performed on all available ECG leads and on a restricted set without the V1–V2 combination. Previously published angiographic scoring tools were adapted for rating and localizing the coronary pathology by two approaches and applied on 174 patients undergoing angiography.
Results: QTdMean was significantly higher than that reported in previous material with unselected chest pain patients (55 vs 40 ms). QTdiffMean correlated strongly with QTdMean. No differences in QTdMean were detected between patients with different angiographical scores. No relation could be shown between the region with dominating coronary pathology as expressed by the scoring tools and the localization of QTdiffMean.
Conclusions: QTd in ischemia seems to be increased by a mechanism unrelated to localization and severity of coronary disease.
Document Type: Research Article
Affiliations: 1: Department of Cardiology, Norrland University Hospital, 901 85 Umea, Sweden 2: Department of Cardiology, University Hospital, 701 85 Örebro, Sweden 3: Department of Cardiology, Akademiska Hospital, 751 85 Uppsala, Sweden
Publication date: January 1, 2003