A smartphone application for semi-automated QT interval analysis based on a snapshot of an electrocardiogram trace displayed on a patient monitor.

Abstract

We developed a smartphone application (SMART-QT application) that can semi-automatically measure QT and QTc intervals based on a snapshot of the electrocardiogram (ECG) trace and the heart rate displayed on a patient monitor. In this study, we aimed to validate the SMART-QT application. In this prospective single-center method comparison study, we measured QT and QTc intervals with the SMART-QT application (QT_APP and QTc_APP; test method) and simultaneously manually measured QT and QTc intervals from a 12-lead ECG (QT_REF and QTc_REF; reference method) in 57 adult volunteers and patients who had sinus rhythm and no acute or chronic cardiac comorbidities. To investigate the agreement between QT_APP and QT_REF and between QTc_APP and QTc_REF, we performed Bland-Altman analyses and calculated the mean of the differences, the standard deviation, and the 95%-limits of agreement (95%-LOA). We defined clinically acceptable agreement as maximum mean of the differences ± standard deviation of 20 ± 20 ms. The mean of the differences between QT_APP and QT_REF was 14 ± 20 ms (95%-LOA -26 to 54 ms). The mean of the differences between QTc_APP and QTc_REF was 13 ± 15 ms (95%-LOA -16 to 42 ms). The agreement between QT_APP and QT_REF and between QTc_APP and QTc_REF was clinically acceptable in adult volunteers and patients without cardiac comorbidities.