Abstract 15680: Validation of Remote Measurement of the Qtc Intervals Using an Apple Watch

Abstract

Introduction: In many circumstances, especially in the Covid-19 period, it could be necessary to measure the QT interval repeatedly even daily. Hypothesis: The aim of the study was to evaluate the feasibility of remote measuring LI-LII and V2 leads with using a commercially available Apple Watch Series 4. Methods: The accuracy of the QTc calculation with the smartwatch compared to the standard ECG was tested using di!erent formulae. One hundred patients admitted to our CCU were studied. LI-LII and V2 tracings were obtained immediately after the recording of the standard 12-lead ECG. The LI was recorded with the smartwatch on the left wrist and the right index finger on the crown; LII was obtained with the watch on the left lower abdomen and the right index finger on the crown; V2 lead was recorded with a smartwatch in the fourth intercostal space left parasternal with the right index finger on the crown. All recorded 30” ECGs were digitally stored using the health application of an iPhone Series 10 in the pdf format. The advantage of saving the ECG in pdf format is that it can be sent also via e-mail. Results: There was an agreement between the QTLI, QT-LII, QT-V2 and QT mean intervals of smartphone electrocardiography tracings and standard electrocardiography using Spearman’s correlation coefficient of 0.881; 0.885; 0.801; 0.911 respectively [p<0.001]. The reliability of the mean QTc measurements was tested with Bland-Altman analysis using Bazett’s, Friedericia’s, and Framingham’s formulas between standard ECG and smartwatch(Figure). Conclusions: These data demonstrated the feasibility to measure the QTc in LI, LII and V2 leads with a smartwatch with results comparable to that performed with the standard ECG. These data could have an important clinical impact both for the widespread di!usion of smartwatches and for the monitoring of drug-induced QT interval prolongation, especially in the Covid-19 era.