Table 3.
Multivariable competing risk analysis for the risk of SCD and incident CHD associated with different ECG variables
| ECG variable* | Definite SCD HR (95% CI)† | Incident CHD HR (95% CI)† | p Value‡ |
|---|---|---|---|
| ECG-LVH | 1.74 (1.03 to 2.93) | 1.59 (1.30 to 1.94) | 0.7522 |
| ECG-LV mass | 1.31 (1.06 to 1.61) | 1.14 (1.06 to 1.23) | 0.2116 |
| Spatial QRST angle | 1.30 (1.15 to 1.47) | 1.19 (1.14 to 1.24) | 0.1835 |
| Spatial T axis | 1.14 (1.03 to 1.27) | 1.10 (1.06 to 1.15) | 0.5540 |
| Frontal QRST angle | 1.17 (1.06 to 1.28) | 1.13 (1.09 to 1.17) | 0.4737 |
| Heart rate | 1.21 (1.07 to 1.37) | 1.05 (1.01 to 1.10) | 0.0398 |
| QTc duration (ms) | 1.19 (1.08 to 1.31) | 1.05 (1.01 to 1.09) | 0.0158 |
| T wave inversion§ | 2.03 (1.49 to 2.75) | 1.41 (1.27 to 1.56) | 0.0265 |
| ST depression§ | 2.44 (1.69 to 3.51) | 1.66 (1.45 to 1.91) | 0.0532 |
| STJ in I (μv) | 0.84 (0.74 to 0.95) | 0.91 (0.87 to 0.95) | 0.2310 |
| STJ in II (μv) | 0.78 (0.69 to 0.89) | 0.96 (0.92 to 1.00) | 0.0029 |
| STJ in aVF (μv) | 0.83 (0.73 to 0.94) | 1.00 (0.96 to 1.04) | 0.0068 |
| STJ in aVL (μv) | 0.98 (0.86 to 1.12) | 0.93 (0.89 to 0.97) | 0.4318 |
| ST60 in I (μv) | 0.77 (0.68 to 0.87) | 0.86 (0.82 to 0.90) | 0.0971 |
| ST60 in II (μv) | 0.83 (0.73 to 0.94) | 0.92 (0.88 to 0.96) | 0.1334 |
| ST60 in III (μv) | 1.05 (0.92 to 1.19) | 1.05 (1.01 to 1.10) | 0.9766 |
| ST60 in aVL (μv) | 0.83 (0.73 to 0.94) | 0.88 (0.85 to 0.92) | 0.3241 |
| STJ in V1 (μv) | 1.07 (0.95 to 1.21) | 1.10 (1.05 to 1.15) | 0.6951 |
| STJ in V2 (μv) | 0.93 (0.81 to 1.07) | 1.10 (1.05 to 1.15) | 0.0251 |
| STJ in V3 (μv) | 0.86 (0.75 to 0.99) | 1.04 (1.00 to 1.09) | 0.0105 |
| STJ in V4 (μv) | 0.85 (0.75 to 0.96) | 0.96 (0.92 to 1.00) | 0.0774 |
| STJ in V5 (μv) | 0.83 (0.74 to 0.93) | 0.93 (0.89 to 0.97) | 0.0841 |
| STJ in V6 (μv) | 0.82 (0.73 to 0.92) | 0.91 (0.87 to 0.95) | 0.1542 |
| ST60 in V1 (μv) | 1.10 (0.98 to 1.25) | 1.14 (1.09 to 1.18) | 0.6588 |
| ST60 in V2 (μv) | 0.91 (0.78 to 1.05) | 1.10 (1.05 to 1.15) | 0.0155 |
| ST60 in V4 (μv) | 0.84 (0.73 to 0.97) | 0.93 (0.89 to 0.98) | 0.1722 |
| ST60 in V5 (μv) | 0.81 (0.72 to 0.92) | 0.88 (0.84 to 0.92) | 0.2114 |
| ST60 in V6 (μv) | 0.82 (0.72 to 0.92) | 0.87 (0.84 to 0.91) | 0.2668 |
Other ECG variables tested for predictive value but not found significant for either outcomes in the preliminary analysis or the competing analysis were excluded from the table. This included QRS duration, spatial QRS axis, ST60 in V3, STJ in III, ST60 in aVF, the amplitude and duration of P, P′, R, R′, Q, S and S′ waves, the R intrinsicoid deflection, T and T′ amplitude, duration and area in each of the 12 ECG leads as well as total QRS duration, axis and area, QT (and QTc by Bazett) duration, PR duration, P wave axis, T wave axis, and time domain heart rate variability indices of SDNN and RMSSD and ST elevation by Minnesota Code.
Unless described otherwise, HRs for continuous variables are per 1 SD increase and for the abnormal value for categorical variables adjusted for the variables in table 2.
Assessing equivalence of HRs for the two end points.
Abnormally inverted T wave and significant ST depression were defined by Minnesota Code as abnormality in any of the ECG lead groups: anterior, lateral or inferior.
SCD, sudden cardiac death; CHD, coronary heart disease; STJ, ST height as measured at the J point; ST60, ST height as measured at 60 ms after the J point.