QT-RR Adaptation Time Lag Estimation and its Dependence on Heart Rate Trend Frequency Content in Exercise Stress Testing

A new model for the estimation of the QT-RR adaptation time lag using exercise ECG stress testing has been proposed, assuming a linear heart rate trend during the test. In this work, simulated ECGs have been generated based on heart rate patterns with oscillations at different frequencies to demonstrate that the assumption can be relaxed so that the QTRR adaptation time lag can be adequately estimated for any heart rate trend whose frequency content is below a certain frequency, which depends on the QT-RR time lag.