QT and QTa interval duration and dispersion during stress test in coronary heart disease and ventricular arrhythmia patients

Abstract

Aim. То investigate the link between dynamics of QT and QTa duration and dispersion, corrected QT and QTa (QTc, QTac) in coronary heart disease (CHD) patients undergoing treadmill stress test, with ventricular arrhythmia registration. Material and metliods. In total, 77 patients with Functional Class II-FV angina were examined (mean age 51,1+8,1 years). All patients underwent treadmill stress test and coronary angiography. According to stress test results, two groups were identified: Group I (n=63) - without cardiac arrhythmias, and Group II (n=14) - with ventricular ectopic activity. Before and after stress test, QT, QTa, QTc, and QTac duration and dispersion were calculated. Results. During stress test, dQT and dQTc increased in both groups. In patients with ventricular arrhythmias, mean dQTa and dQTac decreased after stress test. In both groups, there was no significant difference in mean QT, QTc, QTa, or QTac duration before and after stress test. Conclusion. In CHD patients, ischemia-mediated dQT changes could be linked to terminal T wave variability. Reduced dQTa, as well as increased dQT, in stress test might reflect increased risk of ventricular arrhythmias in CHD patients.

Keywords

• qt interval dispersion
• qta interval
• ventricular arrhythmias
• stress test
• coronary heart disease