The relation of QT dispersion and localized QT difference to coronary pathology in a population with unstable

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Milos Kesek1, Anders Englund, Tomas Jernberg

  • 1Department of Cardiology, Norrland University Hospital, 90185 Umea, Sweden. milos.kesek@zeta.telenordia.se

Annals of Noninvasive Electrocardiology : the Official Journal of the International Society for Holter and Noninvasive Electrocardiology, Inc
|July 10, 2003
PubMed

Insights

QT dispersion (QTd), a marker of heart repolarization, is elevated in patients with unstable coronary artery disease. However, this increase is not linked to the location or severity of coronary artery blockages.

Area of Science:

  • Cardiology
  • Electrophysiology
  • Ischemic Heart Disease

Background:

  • QT dispersion (QTd) is a prognostic indicator in various patient groups.
  • QTd elevation is observed in conditions involving ischemia, potentially reflecting repolarization inhomogeneity.
  • The underlying mechanism of QTd increase during ischemia requires further elucidation.

Purpose of the Study:

  • To investigate the relationship between QT dispersion and angiographic measures in patients with unstable coronary artery disease.
  • To explore potential local mechanisms contributing to QT dispersion during ischemia.

Main Methods:

  • Utilized data from 276 patients in the FRISC II trial.
  • Measured mean QT dispersion (QTdMean) over 27 hours post-admission.
  • Assessed maximal difference in QT between adjacent ECG leads (QTdiffMean) and correlated with angiographic scores in 174 patients.

Main Results:

  • QTdMean was significantly higher (55 ms) compared to unselected chest pain patients (40 ms).
  • QTdiffMean showed a strong correlation with QTdMean.
  • No significant differences in QTdMean were found based on angiographical scores or coronary pathology localization.

Conclusions:

  • QT dispersion in ischemic conditions appears to be influenced by factors independent of coronary artery localization and severity.
  • The mechanism driving increased QTd in ischemia may not be directly related to local coronary pathology.
Abstract

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