Table 1. Patient characteristics and ECG measurements among subjects with SCD (cases) and without SCD (controls).
| Total subjects (n = 695) |
|||
|---|---|---|---|
| Categories | Cases (n = 353) |
Controls (n = 342) |
P value* |
| Age (yr) | 66.6 (65.1 – 68.1) | 64.7 (63.4 – 66.0) | 0.06 |
| Male | 237 (67.1%) | 236 (69.0%) | 0.60 |
| TpTe (ms) | 89.4 (87.7 – 91.2) | 76.1 (74.8 – 77.4) | < 0.0001 |
| Prolonged TpTe† | 193 (54.7%) | 75 (21.9%) | < 0.0001 |
| QTc (ms) | 447.4 (443.0 – 451.8) | 422.1 (418.3 – 425.8) | < 0.0001 |
| Prolonged QTc† | 208 (58.9%) | 106 (31.0%) | < 0.0001 |
| TpTe/QT | 0.22 (0.22 – 0.23) | 0.19 (0.19 – 0.19) | < 0.0001 |
| QRSD (ms)‡ | 100.5 (97.9 – 103.1) | 96.5 (94.5 – 98.4) | 0.01 |
| Prolonged QRSD† | 61 (17.3%) | 44 (12.9%) | 0.10 |
| Diabetes | 139 (39.4%) | 115 (33.6%) | 0.12 |
| Severe LVSD Missing§ |
52 (28.9%) 173 (49.0%) |
16 (11.6%) 204 (59.6%) |
0.0002 |
| Obesity Missing§ |
89 (32.0%) 75 (21.2%) |
133 (40.4%) 13 (3.8%) |
0.03 |
| Hypertension | 260 (73.6%) | 237 (69.3%) | 0.20 |
| Sleep apnea | 39 (11.0%) | 30 (8.8%) | 0.32 |
Results presented as n (%) or mean (95% CI).
*
p-value from Pearson chi-square test for categorical variables and t-test for continuous variables.
†
Prolonged TpTe defined as > 85 ms; prolonged QTc defined as > 430 ms for males and > 450 ms for females [16]; IVCD defined as QRSD≥ 120 ms; severe LVSD defined as ejection fraction ≤ 35%.
‡
QRSD as reported on the ECG recording. TpTe and QT intervals were manually measured.
§
For variables with missing values, proportions and p-values are calculated using the non-missing data as the denominator.
LVSD, Left ventricular systolic dysfunction; QRSD, QRS duration; QTc, corrected QT interval; SCD, sudden cardiac death; TpTe, Tpeak to Tend interval.