Repolarization lability measured on 10-second ECG by spatial TT ' angle: Reproducibility and agreement with QT variability

作者：Feeny Albert; Han Lichy; Tereshchenko Larisa G^*

来源：Journal of Electrocardiology, 2014, 47(5): 708-715.

DOI：10.1016/j.jelectrocard.2014.06.003

• Repolarization
• ECG
• Spatial TT ' angle

Background: Reproducibility of spatial TT' angle on the 10-second ECG and its agreement with QT variability has not been previously studied.
Methods: We analyzed 2 randomly selected 10-second segments within 3-minute resting orthogonal ECG in 172 healthy IDEAL study participants (age 38.1 +/- 15.2 years, 50% male, 94% white). Repolarization lability was measured by the QT variance (QTV), short-term QT variability (STY (QT)), and spatial TT' angle. Bland-Altman analysis was used to assess the agreement between different log-transformed metrics of repolarization lability, and to assess the reproducibility.
Results: The heart rate showed a very high reproducibility (bias 0.14%, Lin's rho_c = 0.99). As expected, noise suppression by averaging improves reproducibility. Agreement between two 10-second LogQTV was poor (bias -0.04; 95% limits of agreement [-1.89; 1.81]), while LogSTV(QT) (0.04 [-1.01; 1.10]), and especially LogTT' angle (-0.009 [-0.84; 0.82]) was better.
Conclusion: TT' angle is a satisfactory reproducible metric of repolarization lability on the 10-second ECG.