Clinical applicability of QT formulae to correct QT interval

The QT interval on the electrocardiogram serves as a measure of ventricular action potential duration, encompassing both ventricular activation and recovery processes. Specifically, it is defined as the interval commencing from the onset of the QRS complex and concluding at the end of the T wave. Accurate determination of the T wave termination point is achieved through the employment of the maximum slope intercept method, which identifies the end of the T wave as the intersecting point between the isoelectric line and the tangent drawn along the steepest downward slope of the T wave. This chapter reviews the historical perspectives, advantages, disadvantages and clinical applicability of the methods by Bazett, Fridericia, Framingham, Hodges, Rautaharju and Dmitrienko for QT interval correction.