Кардиоваскулярная терапия и профилактика (Oct 2011)

Assessment of repolarization heterogeneity in myocardial infarction patients by QT interval time variability (dispersion) and dynamics of the first electrocardiogram derivative

  • O. K. Rybak,
  • Ya. P. Dovgalevskyi,
  • N. V. Furman,
  • A. N. Burlaka,
  • N. Yu. Durnova

DOI
https://doi.org/10.15829/1728-8800-2011-5-51-56
Journal volume & issue
Vol. 10, no. 5
pp. 51 – 56

Abstract

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Aim. To assess the parameters of QT interval variability and time dynamics of T wave velocity characteristics in patients with ST segment elevation myocardial infarction (STEMI). Material and methods. In total, 116 patients with acute MI (mean age 54,9±8,5 years), who underwent urgent thrombolytic therapy (TLT) with alteplase and were admitted to the emergent cardiology department, were followed up. MI diagnosis was verified according to the recommendations by the Society of Cardiology of the Russian Federation (2007) and the criteria of the universal MI definition (2007). In all patients, an electrocardiogram (ECG) was recorded for 5 minutes, with the assessment of the QT interval time variability, data processing, and creation of the first ECG derivative. Results. The first ECG derivative demonstrates two positive waves in the T wave area of the initial ECG. Waves T1 and T2 reflect smoothed modules of the initial T wave increase and decrease velocity, respectively. Therefore, in STEMI patients, the parameters of the time dynamics of T wave velocity could be assessed by the markers of time heterogeneity of myocardial repolarization. In anterior MI, compared to posterior MI, a significant increase in heart-rate adjusted QT interval dispersion (DQTec/VRV) was registered. In patients with effective vs. ineffective TLT, such parameters as variability range (VR (T2/T1)) and DQTec/VRV were significantly different. The first parameter reflects the time dynamics of wave T morphology, while the second characteristic denotes QT interval variability, adjusted for heart rate and the extent of sinus arrhythmia. Conclusion. The proposed parameters of QT interval time variability and time dynamics of wave T velocity characteristics could be used for the risk stratification in MI patients. This method is faster and less expensive than coronary angiography, as a standard visualization procedure.

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