Biological Variation of Corrected QT and QRS Electrocardiogram Intervals: Interpreting Results of Drug-induced Prolongation

We demonstrated a significant difference in QRS duration between healthy males and females as well as a low II, particularly for the QRS interval, indicating that the CV_G is greater than the CV_I among these ECG intervals. In this study we also determined that one ECG is needed to establish a homeostatic set point for patients. If a baseline ECG is available, medical toxicologists would benefit from using the baseline tracing as an internal reference for determining QRS and QTc prolongation in the individual patient rather than a predetermined universal threshold for managing poisoned patients.