Accuracy of mobile 6-lead electrocardiogram device for assessment of QT interval: a prospective validation study

Abstract

Introduction Ambulatory assessment of the heart rate–corrected QT interval (QTc) can be of diagnostic value, for example in patients on QTc-prolonging medication. Repeating sequential 12-lead electrocardiograms (ECGs) to monitor the QTc is cumbersome, but mobile ECG (mECG) devices can potentially solve this problem. As the accuracy of single-lead mECG devices is reportedly variable, a multilead mECG device may be more accurate. Methods This prospective dual-centre study included outpatients visiting our cardiology clinics for any indication. Participants underwent an mECG recording using a smartphone-enabled 6‑lead mECG device immediately before or immediately after a conventional 12-lead ECG recording. Multiple QTc values in both recordings were manually measured in leads I and II using the tangent method and subsequently compared. Results In total, 234 subjects were included (mean ± standard deviation (SD) age: 57 ± 17 years; 58% males), of whom 133 (57%) had cardiac disease. QTc measurement in any lead was impossible due to artefacts in 16 mECGs (7%) and no 12-lead ECGs. Mean (± SD) QTc in lead II on the mECG and 12-lead ECG was 401 ± 30 and 406 ± 31 ms, respectively. Mean (± SD) absolute difference in QTc values between both modalities was 12 ± 9 ms (r = 0.856; p < 0.001). In 55% of the subjects, the absolute difference between QTc values was < 10 ms. Conclusion A 6-lead mECG allows for QTc assessment with good accuracy and can be used safely in ambulatory QTc monitoring. This may improve patient satisfaction and reduce healthcare costs.

Smart devices to measure and monitor QT intervals

“…The authors concluded that 6-lead recordings with this KardiaMobile 6L can provide high-quality ECG recordings that may be useful in clinical medicine and during clinical trials. Bergeman et al ( 18 ) studied the accuracy of the KardiaMobile 6L device for assessment of QT intervals in 234 outpatients visiting a cardiology clinic for any indication. Due to artifacts, it was impossible to perform QTc measurement in any lead in 16 mECGs (7%).…”

“…KardiaMobile 6L can subsequently be connected to the corresponding application through Bluetooth on mobile devices such as tablets and smartphones to record a 30-s 6-lead mECG. It then provides an automated assessment of heart rate and heart rhythm (18). The FDA guidance allows using KardiaMobile 6L to measure QT intervals in patients with COVID-19 (19).…”

Should all electrocardiography be ambulatory?

“…In this issue of the Netherlands Heart Journal , Bergeman and colleagues present a proof-of-concept study in 235 patients to quantify QT intervals with a 6-lead mobile electrocardiogram (mECG) device (Kardia Mobile 6L; AliveCor, Mountain View, CA, USA) [ 6 ]. For AF detection, this device is more accurate than single-lead devices [ 7 ].…”

“…Of the 234 mECG recordings, 33 did not allow for QT determination in lead I and 31 not in lead II; neither lead was suitable in 16 patients (7%) [ 6 ]. The QT interval could not be measured from lead I or II in 43 and 3 conventional ECGs, respectively, and in neither lead in one patient.…”

“…The authors rightfully make the point that mECG measurement of the QT interval is feasible [ 6 ]. Does that imply that we should now have our patients record their QT interval in an ambulatory manner?…”