Table 5.
ECG QRS characteristics (duration, amplitude, and morphology) and correlation coefficients comparison between Smartwatch and standard 12-leads ECG.
| Variables | Lead | SW-ECG | 12-Leads ECG | Correlation coefficient* | p-value |
|---|---|---|---|---|---|
| Duration (milliseconds) | DI | 84.13 ± 18.35 | 101.92 ± 21.02 | 97.3 % | <0.05 |
| V1 | 96.43 ± 21.29 | 102.04 ± 19.32 | 98.1 % | <0.05 | |
| V3 | 96.99 ± 21.13 | 102.74 ± 18.52 | 97.6 % | <0.05 | |
| V6 | 85.13 ± 22.41 | 103.04 ± 20.41 | 96.3 % | <0.05 | |
| Amplitude (millivolts) | DI | 7.9 ± 7.83 | 9,72 ± 6.22 | 68.7 % | <0.05 |
| V1 | 2.36 ± 1.79 | 8.48 ± 4.22 | 69.6 % | <0.05 | |
| V3 | 4.00 ± 2.84 | 9.08 ± 3.92 | 77.6 % | <0.05 | |
| V6 | 11.06 ± 8.63 | 9.88 ± 5.02 | 80 % | <0.05 | |
| Morphology (Narrow/Wide) | DI | N = 124/W = 13 | N = 110/W = 27 | 84.3 % | <0.05 |
| V1 | N = 110/W = 26 | N = 108/W = 29 | 68.9 % | <0.05 | |
| V3 | N = 108/W = 28 | N = 105/W = 26 | 66.6 % | <0.05 | |
| V6 | N = 114/W = 22 | N = 106/W = 27 | 53 % | <0.05 | |
| N: Narrow/W: Wide. | |||||
A strong correlation between the segment ST of the SW and standard ECG was found, except for DI lead, where the correlation coefficient was 55 %, as reported in Table 6.