Table 3.
Comparison of vital signs, ECG variables, and HRV parameters in patients with and without MACE within 30 days of arrival at the ED
| No MACE | MACE | P-value | |
|---|---|---|---|
| (n = 509) | (n = 254) | ||
| Vital signs, μ (σ) | |||
| Temperature | 36.4 (0.8) | 36.4 (0.7) | 0.517 |
| Heart rate | 75 (22) | 81 (23) | 0.001* |
| Respiratory rate | 18 (1) | 18 (1) | 0.791 |
| Systolic BP | 139 (33) | 138 (41) | 0.690 |
| Diastolic BP | 75 (18) | 78 (21) | 0.005* |
| SpO2 | 99 (3) | 99 (3) | 0.505 |
| Pain score | 2 (4) | 2 (5) | 0.090 |
| ECG variables, no. (%) | |||
| ST elevation | 13 (2.6) | 52 (20.6) | <0.001* |
| ST depression | 13 (2.6) | 53 (20.9) | <0.001* |
| T inversion | 82 (16.1) | 69 (27.2) | <0.001* |
| Q wave | 17 (3.3) | 35 (13.8) | <0.001* |
| QT prolongation | 159 (31.2) | 102 (40.2) | 0.015* |
| Left axis deviation | 36 (7.1) | 18 (7.1) | 1.000 |
| Right axis deviation | 15 (2.9) | 8 (3.1) | 1.000 |
| LBBB | 3 (0.6) | 2 (0.8) | 1.000 |
| RBBB | 36 (7.1) | 15 (5.9) | 0.645 |
| IVCD | 3 (0.6) | 11 (4.3) | 0.001* |
| LAA | 7 (1.4) | 5 (2.0) | 0.546 |
| LVH | 62 (12.2) | 41 (16.1) | 0.144 |
| RVH | 5 (1.0) | 1 (0.4) | 0.669 |
| HRV parameters, μ (σ) | |||
| Average RR | 0.824 (0.241) | 0.770 (0.233) | 0.001* |
| SD RR | 0.035 (0.028) | 0.029 (0.031) | 0.010* |
| Average HR | 73.13 (21.16) | 78.11 (23.31) | 0.001* |
| SD HR | 3.27 (2.66) | 2.99 (2.30) | 0.135 |
| RMSSD | 0.028 (0.031) | 0.021 (0.031) | 0.001* |
| NN50 | 10.0 (26) | 6.0 (21) | 0.018* |
| pNN50 | 2.85 (8.42) | 1.55 (7.59) | 0.013* |
| Triangular index | 2.97 (1.96) | 2.87 (1.94) | 0.640 |
| TINN | 0.130 (0.118) | 0.102 (0.113) | 0.002* |
| Total power | 0.470 (0.140) | 0.485 (0.155) | 0.428 |
| VLF power | 0.217 (0.169) | 0.246 (0.202) | 0.030* |
| LF power | 0.113 (0.102) | 0.110 (0.083) | 0.265 |
| Normalized LF | 50.56 (30.52) | 52.99 (35.85) | 0.463 |
| HF | 0.113 (0.110) | 0.098 (0.110) | 0.029* |
| Normalized HF | 49.44 (30.52) | 47.01 (35.85) | 0.463 |
| LF/HF ratio | 1.02 (1.33) | 1.13 (1.68) | 0.428 |
Vital signs and heart rate variability (HRV) parameters are expressed as mean (μ) and standard deviation (σ). MACE major adverse cardiac events, BP blood pressure, ECG electrocardiograph, LBBB left bundle branch block, RBBB right bundle branch block, IVCD intraventricular conduction defect, LAA left atrial abnormality, LVH left ventricular hypertrophy, RVH right ventricular hypertrophy, HRV heart rate variability, NN normal-to-normal, SD standard deviation, RMSSD root mean square of successive differences, SpO 2 pulse arterial oxygen saturation, TINN triangular interpolation NN, VLF very low frequency, LF low frequency, HF high frequency. *P < 0.05