Department of General Practice, Amsterdam Public Health Research Institute, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.
Department of Cardiology, Onze Lieve Vrouwe Gasthuis (OLVG), Amsterdam, Noord-Holland, The Netherlands.
BMJ Open. 2021 Nov 3;11(11):e055072. doi: 10.1136/bmjopen-2021-055072.
To determine the accuracy of QT measurement in a smartphone-operated, single-lead ECG (1L-ECG) device (AliveCor KardiaMobile 1L).
Cross-sectional, within-patient diagnostic validation study.
SETTING/PARTICIPANTS: Patients underwent a 12-lead ECG (12L-ECG) for any non-acute indication in primary care, April 2017-July 2018.
Simultaneous recording of 1L-ECGs and 12L-ECGs with blinded manual QT assessment. OUTCOMES OF INTEREST: (1) Difference in QT interval in milliseconds (ms) between the devices; (2) measurement agreement between the devices (excellent agreement <20 ms and clinically acceptable agreement <40 ms absolute difference); (3) sensitivity and specificity for detection of extreme QTc (short (≤340 ms) or long (≥480 ms)), on 1L-ECGs versus 12L-ECGs as reference standard. In case of significant discrepancy between lead I/II of 12L-ECGs and 1L-ECGs, we developed a correction tool by adding the difference between QT measurements of 12L-ECG and 1L-ECGs.
250 ECGs of 125 patients were included. The mean QTc interval, using Bazett's formula (QTcB), was 393±25 ms (mean±SD) in 1L-ECGs and 392±27 ms in lead I of 12L-ECGs, a mean difference of 1±21 ms, which was not statistically different (paired t-test (p=0.51) and Bland Altman method (p=0.23)). In terms of agreement between 1L-ECGs and lead I, QTcB had excellent agreement in 66.9% and clinically acceptable agreement in 93.4% of observations. The sensitivity and specificity of detecting extreme QTc were 0% and 99.2%, respectively. The comparison of 1L-ECG QTcB with lead II of 12L-ECGs showed a significant difference (p=<0.01), but when using a correction factor (+9 ms) this difference was cancelled (paired t-test (p=0.43) or Bland Altman test (p=0.57)). Moreover, it led to improved rates of excellent (71.3%) and clinically acceptable (94.3%) agreement.
Smartphone-operated 1L-ECGs can be used to accurately measure the QTc interval compared with simultaneously obtained 12L-ECGs in a primary care population. This may provide an opportunity for monitoring the effects of potential QTc-prolonging medications.
确定智能手机操作的单导联心电图（1L-ECG）设备（AliveCor KardiaMobile 1L）中 QT 测量的准确性。
患者于 2017 年 4 月至 2018 年 7 月在初级保健机构因任何非急性原因进行 12 导联心电图（12L-ECG）检查。
同时记录 1L-ECG 和 12L-ECG，并进行盲法手动 QT 评估。
共纳入 125 例患者的 250 份心电图。使用 Bazett 公式（QTcB）计算的平均 QTc 间期在 1L-ECG 中为 393±25ms（平均值±标准差），在 12L-ECG 的 I 导联中为 392±27ms，平均差异为 1±21ms，无统计学差异（配对 t 检验（p=0.51）和 Bland-Altman 方法（p=0.23））。在 1L-ECG 和 I 导联之间的一致性方面，QTcB 在 66.9%的情况下具有极好的一致性，在 93.4%的情况下具有可接受的一致性。检测极端 QTc 的灵敏度和特异性分别为 0%和 99.2%。与 12L-ECG 的 II 导联相比，1L-ECG 的 QTcB 具有显著差异（p<0.01），但使用校正因子（+9ms）后，这种差异被消除（配对 t 检验（p=0.43）或 Bland-Altman 检验（p=0.57））。此外，这导致极好（71.3%）和可接受（94.3%）一致性的比率提高。
智能手机操作的 1L-ECG 可用于准确测量与初级保健人群中同时获得的 12L-ECG 相比的 QTc 间期。这可能为监测潜在的 QT 延长药物的效果提供机会。
