Towards Accurate and Model-Free QT Correction.

In the electrocardiogram (ECG), the QT interval is an important metric of risk for various adverse cardiovascular events and a key measure in cardiotoxicology. The main challenge in the interpretation of the QT measurement is its dependence on the heart rate, i.e., the RR intervals. To correct the QT interval for heart rate, a multitude of approximative methods have been developed, e.g., the power-law formulas of Bazett and Fridericia that are still in clinical use. However, these methods are known to under- or overcorrect the QT intervals, and none of the methods developed to date are universally applicable to different conditions. Here we present a QT correction method that is not based on models or empirical data, but directly utilizes information transfer between the RR and QT intervals during the measurement. The method dynamically adapts to a multitude of previous RR intervals and gives the QT correction as an output. We outline the essential principles of the method and provide a set of test results that demonstrate the stability of the corrected QT values in comparison with the conventional correction methods.