| Abstract [eng] |
Each year, 1 in 100 people dies from sudden cardiac death. One of its indicators is a prolonged QT interval. Cardiologists typically assess the QT interval from electrocardiogram (ECG) signals recorded in clinical settings. To enable early detection of QT prolongation or monitor it when using medications with side effects, ECG monitoring is essential not only in clinics but also beyond them. This creates a need to monitor the QT interval using wearable devices. In this study, we selected three well-known methods for QT interval duration estimation: the tangential, threshold-based, and Philips methods. We evaluated these methods and compared them using signals recorded by the wearable device KTU_Watch. We annotated the QT intervals manually. For additional comparison, we used a reference ECG signals from the MUSIC database. The analysis of signals recorded with the wearable device showed that the tangential method estimates QT interval durations more accurately than the threshold-based or Philips methods. The tangential method achieved a root mean square error (RMSE) of 17.5 ms, with a systematic error of –14.6 ms and a random error of ±19.6 ms. The Philips method reached an RMSE of 22.7 ms, with a systematic error of –5.5 ms and a random error of ±44.5 ms. The threshold-based method was the least accurate, with a 30.2 ms RMSE, a systematic error of 22.7 ms, and a random error of ±40.3 ms. During the study, we observed an issue of incorrect QT interval annotations in the MUSIC reference database, particularly in cases of non-standard ECG morphology caused by inverted T-waves and tachycardia. |
