Repolarization lability measured on 10-second ECG by spatial TT' angle: reproducibility and agreement with QT
Albert Feeny1, Lichy Han1, Larisa G Tereshchenko2
1Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, USA.
Journal of Electrocardiology
|July 12, 2014
Summary
The spatial TT' angle demonstrates satisfactory reproducibility for measuring repolarization lability on a 10-second ECG. This metric shows better agreement compared to QT variance (QTV) and short-term QT variability (STV(QT)).
Area of Science:
- Cardiology
- Electrocardiography
- Repolarization analysis
Background:
- The reproducibility of the spatial TT' angle on short ECG recordings and its agreement with QT variability remain uninvestigated.
- Assessing repolarization lability is crucial for understanding cardiac electrical stability.
Purpose of the Study:
- To evaluate the reproducibility of the spatial TT' angle on a 10-second ECG.
- To compare the agreement of the spatial TT' angle with QT variance (QTV) and short-term QT variability (STV(QT)) for repolarization lability assessment.
Main Methods:
- Analysis of 2 randomly selected 10-second ECG segments from 172 healthy participants.
- Measurement of repolarization lability using spatial TT' angle, QTV, and STV(QT).
- Bland-Altman analysis applied to log-transformed metrics to assess agreement and reproducibility.
Main Results:
- Heart rate reproducibility was very high (bias 0.14%, Lin's rho_c=0.99).
- Agreement between two 10-second LogQTV measurements was poor (bias -0.04).
- LogSTV(QT) showed better agreement (bias 0.04), while the LogTT' angle demonstrated the best agreement (bias -0.009) and reproducibility.
Conclusions:
- The spatial TT' angle is a sufficiently reproducible metric for assessing repolarization lability on a 10-second ECG.
- The spatial TT' angle offers better agreement than QTV and STV(QT) for short ECG recordings.
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