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Comparison of QT and QTc Interval Measurements from Bedside Electrocardiograms between Expert Nurses, Bedside Nurses and Computerized Measurements: A Pilot Study


Introduction: Prolongation of the QT/QTc (heart rate corrected) >500 milliseconds (msec) measured on the electrocardiogram (ECG) in hospitalized patients is associated with torsade de pointes (TdP). While some bedside ECG monitors now offer continuous QT/QTc software, agreement of these measurements to bedside and/or expert nurses has not been evaluated. Purpose: The purpose of this study was to compare QT/QTc measurements between expert nurses, bedside nurses, both using electronic calipers, and continuous computerized measurements. Methods: Prospective observational study in three intensive care units (ICUs). Up to two QT/QTc measurements per patient were examined. QT/QTc agreement was examined using Bland-Altman analysis. Results: The study included 34 ICU patients with 57 QT/QTc measurements. Conclusion: Expert nurses consistently measured a longer QT/QTc as compared to bedside nurses and computerized measurements and computerized measurements were consistently longer than bedside nurse measurements. While there was a statistical difference between QT/QTc measurements between groups, the differences do not appear to be clinically significant due to the small mean bias differences. However, future studies are warranted to corroborate our findings and should include comparisons to standard 12-lead ECG QT/QTc measurements.

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