[QT dispersion in surface ECG and QT dynamics in long-term ECG in patients with coronary heart disease in the chronic post-infarct stage with and without ventricular tachyarrhythmias--correlation with other risk parameters].
QT-dispersion (QTD) in 12-lead surface-ECG and QT-dynamics in Holter-ECG, defined as the time-course of the frequency corrected QT-interval (mQTc), were determined in 42 patients with coronary artery disease in chronic postinfarction stadium without ventricular tachyarrhythmias (CAD/VTA-) and in 24 CAD patients with ventricular tachyarrhythmias (CAD/VTA+). 14 healthy volunteers served as control group (CG). Correlations with hemodynamic data (LVEF, severity of CAD) and with other risk-parameters (ventricular late potentials, short-time heart rate variability) were calculated. QTD in CAD/VTA-was significantly higher compared to CG (48.4 ms+/- 19.6 vs 31.4 ms +/- 9.8, p < 0.05). There were no intergroup differences in QT-dynamics. CAD/VTA+ patients showed the highest QTD-values (59.5 ms +/- 31.1, p < 0.05 compared to CG/CAD/VTA0) and a significantly altered QT-dynamics compared to CG/CAD/VTA- (mQTc: 431.3 ms +/- 38.8 vs 400.8 ms +/- 25.5 vs 406.3 ms +/- l0.6, p < 0.05). Only parameters of QTD were significantly correlated to severity of CAD (r = +0.41, p < 0.01) and to LVEF (r = 0.43, p < 0.01). We did not find significant correlations between the parameters of QT-dispersion/QT-dynamics among one another and to the risk-parameters. These results indicate that the QT-dispersion in CAD-patients also in chronic post-infarction stadium is elevated and that CAD-patients with VTA are characterized by an altered QT-dynamics. Parameters of both methods are independent of other validated risk-parameters. So the measurement of QT-dispersion and QT-dynamics as markers of inhomogenous repolarization could contribute to an improvement of risk-stratification of CAD-patients.
Walter
T
T
Abteilung Kardiologie/Angiologie, Universität Leipzig.
Griessl
G
G
Kluge
P
P
Neugebauer
A
A
D003327:Coronary Disease / Q000175:diagnosis* / Q000503:physiopathology; D015716:Electrocardiography, Ambulatory / Q000295:instrumentation*; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology; D006339:Heart Rate / Q000502:physiology; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008133:Long QT Syndrome / Q000175:diagnosis* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000503:physiopathology; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000503:physiopathology; D016277:Ventricular Function, Left / Q000502:physiology