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QT dispersion ratio in patients with unstable angina pectoris (a new risk factor?)
1Selçuk University, School of Medicine, Cardiac Department, Konya, Turkey.
Background:
QT dispersion has been shown to be associated with fatal arrhythmias and sudden death in coronary artery disease. A recent study indicated that marked QT dispersion in electrocardiograms (ECGs) obtained during acute ischemia demonstrated a significant correlation with ventricular fibrillation.
Hypothesis:
This study investigated the ECG parameters for repolarization (QT dispersion, corrected QT, corrected QT dispersion, and QT dispersion ratio) and their interrelation with acute ischemia.
Methods:
QT parameters as well as a newly developed repolarization index, QT dispersion ratio [(QT dispersion/RR interval) x 100] were calculated digitally during rest and ischemia in 32 patients with coronary artery disease (rest angina, Braunwald class III). Results were correlated with clinical consequences, mainly arrhythmias, within a follow-up period of 5 +/- 2 days.
Results:
While most patients had an increase in all four parameters, only the QT dispersion ratio showed a significant difference when correlated with ventricular arrhythmias (p < 0.001, F ratio = 38).
Conclusion:
QT dispersion ratio appears to be a new and promising parameter in predicting ventricular arrhythmias in patients with acute ischemia.