Author Contributions
Conceptualization, S.K., S.-R.L., E.-K.C., H.-J.A., and H.-S.S.; methodology, S.K., S.-R.L., E.-K.C., H.-J.A., and H.-S.S.; software, S.K., S.-R.L., E.-K.C., H.-J.A., and H.-S.S.; validation, S.K., S.-R.L., E.-K.C., H.-J.A., H.-S.S., Y.-S.L., and S.O.; formal analysis, S.K., S.-R.L., E.-K.C., and H.-J.A.; investigation, S.K., S.-R.L., E.-K.C., H.-J.A., and H.-S.S.; resources, S.K., S.-R.L., E.-K.C., H.-J.A., and H.-S.S.; data curation, S.K., S.-R.L., E.-K.C., H.-J.A., and H.-S.S.; writing—original draft preparation, S.K. and S.-R.L.; writing—review and editing, S.K., S.-R.L., E.-K.C., H.-J.A., H.-S.S., Y.-S.L., and S.O.; visualization, S.K. and S.-R.L.; supervision, E.-K.C., Y.-S.L., and S.O.; project administration, E.-K.C., Y.-S.L., and S.O.; funding acquisition, E.-K.C. All authors have read and agreed to the published version of the manuscript.
Conflicts of Interest
S.K., S.-R.L., H.-J.A., and S.O.: None to declare. H.-S.S. and Y.-S.L.: Stockholer of Seers Technology Co., Ltd. E.-K.C. received research grants from Bayer, BMS/Pfizer, Biosense Webster, Chong Kun Dang, Daiichi-Sankyo, Samjinpharm, Sanofi-Aventis, Seers Technology, Skylabs, and Yuhan.
Figure 1.
The measurement setting for ECG monitoring of a study participant. The left panel shows a participant wearing a Holter monitoring and an adhesive single-lead ECG monitoring device (mobiCARE-MC100) simultaneously. The right panel shows the product appearance of mobiCARE-MC100. Abbreviation: ECG, electrocardiogram.
Figure 1.
The measurement setting for ECG monitoring of a study participant. The left panel shows a participant wearing a Holter monitoring and an adhesive single-lead ECG monitoring device (mobiCARE-MC100) simultaneously. The right panel shows the product appearance of mobiCARE-MC100. Abbreviation: ECG, electrocardiogram.
Figure 2.
The Bland–Altman plots for ECG parameters, including total QRS complexes/VEBs/ SVEBs, and burdens of VEBs/SVEBs. The plots drew with 95% CI of limits of agreement and 95% CI of mean difference. The mobiCARE-MC100 served as a reference. Abbreviations: CI, confidence interval; ECG, electrocardiogram; ICC, intraclass correlation coefficient; SD, standard deviation; SVEB, supraventricular ectopic beat; VEB, ventricular ectopic beat.
Figure 2.
The Bland–Altman plots for ECG parameters, including total QRS complexes/VEBs/ SVEBs, and burdens of VEBs/SVEBs. The plots drew with 95% CI of limits of agreement and 95% CI of mean difference. The mobiCARE-MC100 served as a reference. Abbreviations: CI, confidence interval; ECG, electrocardiogram; ICC, intraclass correlation coefficient; SD, standard deviation; SVEB, supraventricular ectopic beat; VEB, ventricular ectopic beat.
Figure 3.
The Bland–Altman plots for ECG parameters, including minimum/average/maximum HR and maximum RR interval. The plots drew with 95% CI of limits of agreement and 95% CI of mean difference. The mobiCARE-MC100 served as a reference. Abbreviations: CI, confidence interval; ECG, electrocardiogram; HR, heart rate; ICC, intraclass correlation coefficient; SD, standard deviation.
Figure 3.
The Bland–Altman plots for ECG parameters, including minimum/average/maximum HR and maximum RR interval. The plots drew with 95% CI of limits of agreement and 95% CI of mean difference. The mobiCARE-MC100 served as a reference. Abbreviations: CI, confidence interval; ECG, electrocardiogram; HR, heart rate; ICC, intraclass correlation coefficient; SD, standard deviation.
Figure 4.
An exemplary case of reporting more VEBs with a single-lead ECG monitoring than with Holter monitoring. The participant had PACs with aberrant conduction (red arrows) in Holter monitoring. However, the aberrant conduction was less clear in this participant because the P-waves are unclear in the single-lead ECG monitoring. Therefore, for the patients with P-waves of low amplitude, a compensatory pause should be considered in addition to the change in QRS morphology when judging a premature ventricular complex or aberrant conduction with the single-lead ECG monitoring. Abbreviations: ECG, electrocardiogram; PAC, premature atrial complex; VEB, ventricular ectopic beat.
Figure 4.
An exemplary case of reporting more VEBs with a single-lead ECG monitoring than with Holter monitoring. The participant had PACs with aberrant conduction (red arrows) in Holter monitoring. However, the aberrant conduction was less clear in this participant because the P-waves are unclear in the single-lead ECG monitoring. Therefore, for the patients with P-waves of low amplitude, a compensatory pause should be considered in addition to the change in QRS morphology when judging a premature ventricular complex or aberrant conduction with the single-lead ECG monitoring. Abbreviations: ECG, electrocardiogram; PAC, premature atrial complex; VEB, ventricular ectopic beat.
Figure 5.
An exemplary case of reporting more SVEBs with a single-lead ECG monitoring than with Holter monitoring. In this participant, non-conducted PACs (red arrows) and conducted PACs (blue arrows) were observed in Holter monitoring, whereas P-waves were rarely visible with the single-lead monitoring. Compared to the sinus rhythm, the P-wave morphology was different in non-conducted and conducted PACs in Holter monitoring. Therefore, detecting SVEBs with single-lead monitoring mostly depends on evaluating RR intervals and QRS morphology. As a result, SVEBs may be overestimated with the single-lead monitoring than with Holter for this case. Abbreviations: ECG, electrocardiogram; PAC, premature atrial complex; SVEB, supraventricular ectopic beat.
Figure 5.
An exemplary case of reporting more SVEBs with a single-lead ECG monitoring than with Holter monitoring. In this participant, non-conducted PACs (red arrows) and conducted PACs (blue arrows) were observed in Holter monitoring, whereas P-waves were rarely visible with the single-lead monitoring. Compared to the sinus rhythm, the P-wave morphology was different in non-conducted and conducted PACs in Holter monitoring. Therefore, detecting SVEBs with single-lead monitoring mostly depends on evaluating RR intervals and QRS morphology. As a result, SVEBs may be overestimated with the single-lead monitoring than with Holter for this case. Abbreviations: ECG, electrocardiogram; PAC, premature atrial complex; SVEB, supraventricular ectopic beat.
Figure 6.
The heart rate trend with adhesive patch-type ECG monitoring device. The raw data from the outlier with significantly higher total QRS complexes with Holter monitoring showed there were significant Bluetooth disconnection periods during the nocturnal period (within the red-rectangled area). Abbreviations: ECG, electrocardiogram.
Figure 6.
The heart rate trend with adhesive patch-type ECG monitoring device. The raw data from the outlier with significantly higher total QRS complexes with Holter monitoring showed there were significant Bluetooth disconnection periods during the nocturnal period (within the red-rectangled area). Abbreviations: ECG, electrocardiogram.
Figure 7.
The outlier with significantly higher maximum heart rate with Holter monitoring. The amplitude of a particular QRS complex (red arrow) was lower than other complexes in the lead I, and this led to undersensing of the QRS complex with the MC-100. Such a particular undersensing led to different measurements of the maximum heart rate.
Figure 7.
The outlier with significantly higher maximum heart rate with Holter monitoring. The amplitude of a particular QRS complex (red arrow) was lower than other complexes in the lead I, and this led to undersensing of the QRS complex with the MC-100. Such a particular undersensing led to different measurements of the maximum heart rate.
Figure 8.
The outlier with different maximum RR intervals between the two devices. Both devices detected the same episode for their detection of the maximum RR interval. However, there was a minute difference in maximum RR intervals (red lines) between both devices (less than 50 ms). We concluded there existed minute differences in detecting R-wave peaks between both devices.
Figure 8.
The outlier with different maximum RR intervals between the two devices. Both devices detected the same episode for their detection of the maximum RR interval. However, there was a minute difference in maximum RR intervals (red lines) between both devices (less than 50 ms). We concluded there existed minute differences in detecting R-wave peaks between both devices.
Table 1.
The specification of the MC-100.
Table 1.
The specification of the MC-100.
Manufacturer | Seers Technology (Seongnam-si, Gyeonggi-do, Republic of Korea) |
Product serial number | mobiCARE-MC100 |
Product appearance | |
Size | Width 29 mm, length 120 mm |
Weight | 8.9 g |
Measurements | Single-lead electrocardiogram in real-time, heart rate, movement activity |
Sensors | Electrodes, accelerometers, gyroscopes |
Connectivity | Bluetooth low energy |
Heart rate measurement range | From 30 to 240 beat-per-minutes |
Sampling rate | 256 Hz |
Battery | Replaceable CR2032H coin cell battery |
Electrode standard | Medical standard 4.0 mm electrode snaps for electrocardiogram |
Operating time | Lasting at least 72 h continuously |
Table 2.
Baseline characteristics of the study participants (total N = 29).
Table 2.
Baseline characteristics of the study participants (total N = 29).
Characteristics | Value |
---|
Demographic factors | |
Age, year | 55.1 ± 12.8 |
Male, % | 14 (48.3) |
Height, cm | 164.5 ± 6.7 |
Weight, kg | 66.6 ± 11.1 |
Body mass index, kg/m2 | 24.5 ± 2.8 |
Comorbidity | |
Hypertension | 10 (34.5) |
Diabetes mellitus | 2 (6.9) |
Congestive heart failure | 1 (3.4) |
Peripheral artery disease | 0 (0) |
Ischemic heart disease | 0 (0) |
Chronic kidney disease | 2 (6.9) |
Chronic liver disease | 1 (3.4) |
Ischemic stroke | 1 (3.4) |
Indication for ECG monitoring 1 | |
Suspicious arrhythmia-related symptoms 2 | 11 (37.9) |
History of arrhythmia | 20 (69.0) |
Premature atrial contraction | 2 (6.9) |
Supraventricular tachyarrhythmia | 3 (10.3) |
Atrial flutter | 1 (3.4) |
Premature ventricular contraction | 12 (41.4) |
Idiopathic ventricular tachycardia | 1 (3.4) |
Second-degree atrioventricular block, Mobitz type 1 | 1 (3.4) |
Table 3.
Comparisons of ECG monitoring between Holter and adhesive single-lead ECG monitoring for the study population.
Table 3.
Comparisons of ECG monitoring between Holter and adhesive single-lead ECG monitoring for the study population.
| Holter | mobiCARE-MC100 | ICC (95% CI) | p-Value for Reliability | p-Value for Mean Difference |
---|
Total participants, N | 29 | 29 | - | - | - |
Noise, % | 0.01 ± 0.01 | 0.04 ± 0.05 1 | - | - | 0.024 |
Total wear time, min 2 | 1403 ± 20 | 1408 ± 20 | - | - | <0.001 |
Total QRS complexes, N | 96,073 ± 13,922 | 94,910 ± 14,510 | 0.991 (0.982–0.996) | <0.001 | 0.024 |
Total VEBs, N | 6 (1–948) | 5 (1–1459) | 1.000 (0.999–1.000) | <0.001 | 0.984 |
Total SVEBs, N | 25 (8–93) | 48 (13–1485) | 0.987 (0.973–0.994) | <0.001 | 0.459 |
Burden of VEBs, % | 0.01 (0–0.96) | 0.01 (0–1.57) | 1.000 (0.999–1.000) | <0.001 | 0.648 |
Burden of SVEBs, % | 0.03 (0.01–0.10) | 0.05 (0.01–1.62) | 0.986 (0.970–0.993) | <0.001 | 0.370 |
Patients with frequent VEBs, N (%) 3 | 4 (13.8) | 4 (13.8) | - | - | >0.999 |
Patients with frequent SVEBs, N (%) 3 | 2 (6.9) | 1 (3.4) | - | - | 0.317 |
Minimum HR, beats/min | 45.9 ± 8.6 | 46.3 ± 8.7 | 0.999 (0.998–1.000) | <0.001 | <0.001 |
Average HR, beats/min | 68.7 ± 10.1 | 69.7 ± 10.5 | 0.994 (0.987–0.997) | <0.001 | 0.003 |
Maximum HR, beats/min | 123.9 ± 24.7 | 123.3 ± 24.5 | 0.994 (0.987–0.997) | <0.001 | 0.442 |
Maximum RR interval, ms | 1560 (1460–1755) | 1570 (1465–1765) | 1.000 (0.999–1.000) | <0.001 | <0.001 |
Table 4.
Comparisons of diagnoses between Holter and adhesive single-lead ECG monitoring by cardiologists.
Table 4.
Comparisons of diagnoses between Holter and adhesive single-lead ECG monitoring by cardiologists.
Patient No. | Holter | MC-100 |
---|
Patient 1 | Frequent PVC 1 | Frequent PVC 1 |
Patient 2 | Frequent PVC 1 | Frequent PVC 1 |
Patient 3 | Predominantly SR 2 | Predominantly SR 2 |
Patient 4 | PAT | PAT |
Patient 5 | Predominantly SR 2 | Predominantly SR 2 |
Patient 6 | Predominantly SR 2 | Predominantly SR 2 |
Patient 7 | Predominantly SR 2 | Predominantly SR 2 |
Patient 8 | PAT | PAT |
Patient 9 | Predominantly SR 2 | Predominantly SR 2 |
Patient 10 | Predominantly SR 2 | Predominantly SR 2 |
Patient 11 | PAT, frequent PAC 1 | PAT |
Patient 12 | Frequent PVC 1 | Frequent PVC 1 |
Patient 13 | Predominantly SR 2 | Predominantly SR 2 |
Patient 14 | Predominantly SR 2 | Predominantly SR 2 |
Patient 15 | Predominantly SR 2 | Predominantly SR2 |
Patient 16 | Second-degree AVB (type 1), NSVT | Second-degree AVB (type 1), NSVT |
Patient 17 | Predominantly SR 2 | Predominantly SR 2 |
Patient 18 | Frequent PVC 1, NSVT | Frequent PVC 1, NSVT |
Patient 19 | Predominantly SR 2 | Predominantly SR 2 |
Patient 20 | Predominantly SR 2 | Predominantly SR2 |
Patient 21 | PAT | PAT |
Patient 22 | Predominantly SR 2 | Predominantly SR 2 |
Patient 23 | Predominantly SR 2 | Predominantly SR 2 |
Patient 24 | Predominantly SR 2 | Predominantly SR 2 |
Patient 25 | SSS | SSS |
Patient 26 | Predominantly SR 2 | Predominantly SR 2 |
Patient 27 | Predominantly SR 2 | Predominantly SR 2 |
Patient 28 | PAT, frequent PAC 1 | PAT, frequent PAC 1 |
Patient 29 | PAT | PAT |
Table 5.
The self-reported questionnaire on using the MC-100 (English-translated version).
Table 5.
The self-reported questionnaire on using the MC-100 (English-translated version).
| Mean ± SD or N (%) |
---|
Usability of the adhesive single-lead ECG monitoring device | |
Did you feel discomfort with the device? (None = 1, Minimal = 2, Some = 3, Much = 4, Very much = 5) | 1.6 ± 1.0 |
Did you feel skin irritability with the device? (None = 1, Minimal = 2, Some = 3, Much = 4, Very much = 5) | 1.8 ± 1.2 |
When do you most feel the discomfort of using the device? | |
During sleep | 3 (10.3) |
During activity | 9 (31.0) |
During rest | 0 (0) |
Did you have detached episode(s) with the device? | 0 (0) |
Usability of the smartphone application for the monitoring device | |
Did you check the application for monitoring your ECG? (None = 1, Minimal = 2, Some = 3, Much = 4, Very much = 5) | 2.4 ± 1.3 |
Did you record an episode with the application when you had symptoms? (None = 1, Minimal = 2, Some = 3, Much = 4, Very much = 5) | 1.7 ± 1.3 |
Was it easy to record your symptom with the application? (None = 1, Minimal = 2, Some = 3, Much = 4, Very much = 5) | 2.5 ± 1.4 |
Did you receive alarms from the application for the device disconnection? | 17 (58.6) |
Overall product evaluation | |
Do you satisfy with using the device? (None = 1, Minimal = 2, Some = 3, Much = 4, Very much = 5) | 4.1 ± 1.0 |
Do you satisfy with using the application? (None = 1, Minimal = 2, Some = 3, Much = 4, Very much = 5) | 4.0 ± 1.2 |
Table 6.
Brief comparisons between the MC-100 and Holter.
Table 6.
Brief comparisons between the MC-100 and Holter.
| MC-100 | Holter |
---|
Manufacturer | Seers Technology | Variable |
Monitoring period | Up to 3 days | Up to 3 days |
ECG channels | 1 | 3–12, variable |
Real-time monitoring | Yes | No |
Weight | 9 g | Typically over 100 g, variable |
Battery | Replaceable commercial coin cell battery | Mostly built-in, variable |
Electrodes | Replaceable commercial ECG electrodes | Replaceable commercial ECG electrodes |
Data storage | User’s smartphone with the application is necessary to monitor and store ECG data. Bluetooth connectivity is required | Built-in memory. Data transmission and processing are processed in the clinic |
Associated components | Electrodes only | Electrodes, leads, symptom recorder, straps, variable |