A Correction Method of Electrocardiographic Interval Subject to Heart Rate

This paper considers the calculation problem of the heart rate-normalized electrocardiographic interval—an important indicator of cardiac performance—for removing its correlation with cardiac cycle length (or heart rate). We suggest a regularized least-squares procedure to calculate the normative interval under a heart rate of 60 bpm. This procedure is applied to recalculate the electrocardiographic interval into the corrected electrocardiographic interval. We demonstrate that the correlation coefficient between the resulting corrected electrocardiographic interval and cardiac cycle length is smaller than in the case of recalculations based on all well-known formulas. Our suggested method of electrocardiographic interval estimation is almost heart rate independent and therefore can be recommended for clinical practice.