Archives of the Turkish Society of Cardiology
QT Dispersion in the Risk Stratification of Patients with Unstable Angina: Correlations with Clinical Course, Troponin-T and Scintigraphy [Turk Kardiyol Dern Ars]
Turk Kardiyol Dern Ars. 1999; 27(1): 20-25

QT Dispersion in the Risk Stratification of Patients with Unstable Angina: Correlations with Clinical Course, Troponin-T and Scintigraphy

Mehmet AKSOY1, Gültekin HOBİKOĞLU1, Metin GÜRSÜRER1, Ayşe EMRE1, Ömer GÖKTEKİN1, İzzet ERDİNLER1, Turgut SİBER1, Birsen ERSEK1

This study sought to evaluate the potential prognostie usefulness of QT dispersion (Qtd) in patients hospitalized with a presumed diagnosis of uns table ang ina. QTd was ealculated at the admission ECG of 62 patients presenting to the emergency department with chest pain at rest. Blood sample w as collected for troponin-T (TnT) measurement and all patients had 25-30 mCi of Tc- 99m sestamibi injeetion. SPECT acquisition was performed within 1-6 hours after the injection. SPECT images were scored using 20 segments on a 5-point seale (O=normal, 4=no uptake) and a segment with a seore ~2 was eonsidered to have a perfusion defect. The cut-off value of ~0.1 ng/ml was used to definc an elevated TnT. All patients had one month follow-up in order to assess cardiac events. Cardiae events oeeurred in 41 patients (no death, 1 ı myocardial infarction, 4 urgent and 26 planned revaseularization dittering follow-up. The mean QTd in patients with eardiae events was signifieantly higher than in those without eardiae events (68±28 vs. 54± 1.14 m s; p=O.O ı ). When patients were divided into subgroups according to the cardiae events, the mean QTd in myoeardial infaretion and in revascularization were 90±25 ms and 60±25 ms, respeetively. QTd in patients with myoeardial infaretion was higher than in patients without eardiae events (p=O.OO 1 ). There w as no s ignifieant differenee in QTd between revaseularization subgroup and patients without eardiac events. ı 9 patients w ith elevated TnT indicaling high risk in unstable angina had greater QTd eompared to patients with normal TnT (74±29 vs. 56±20 ms; p=0.008). Additionally, the mean QTd in 46 patients with perfusion defects was slightly higher than in patients without those (66±27 vs. 53±ı7 ms; p=0.03). There was also a moderate eorrelation between QTd and the number of perfusion defects (r=0.3 ı , p=O.O 1 ). On the other hand, most of the high-risk patients who had myocardial infaretion or urgent revaseularization had QTd greater than the value of 75 ms. In eonclusion, the measurement of QTd in patients w ith unstable angina may be of heıp in the stratifieation of patients at high risk for adverse eardiae vents, in partieular myoeardial infaretion.

Keywords: QT dispersion, SPECT, troponin-T, unstable angina

How to cite this article
Mehmet AKSOY, Gültekin HOBİKOĞLU, Metin GÜRSÜRER, Ayşe EMRE, Ömer GÖKTEKİN, İzzet ERDİNLER, Turgut SİBER, Birsen ERSEK. QT Dispersion in the Risk Stratification of Patients with Unstable Angina: Correlations with Clinical Course, Troponin-T and Scintigraphy. Turk Kardiyol Dern Ars. 1999; 27(1): 20-25
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