Accuracy of mobile 6-lead electrocardiogram device for assessment of QT interval: aprospective validation study.

Abstract

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, amultilead mECG device may be more accurate. This prospective dual-centre study included outpatients visiting our cardiology clinics for any indication. Participants underwent an mECG recording using asmartphone-enabled 6‑lead mECG device immediately before or immediately after aconventional 12-lead ECG recording. Multiple QTc values in both recordings were manually measured in leadsI andII using the tangent method and subsequently compared. In total, 234 subjects were included (mean ± standard deviation (SD) age: 57 ± 17years; 58% males), of whom 133 (57%) had cardiac disease. QTc measurement in any lead was impossible due to artefacts in 16mECGs (7%) and no 12-lead ECGs. Mean (±SD) QTc in leadII 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. A6-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.