Table 1.
Baseline Characteristics of the Study Sample
| Characteristic | Whole Sample (N=7,575) |
Baseline PR ≤200 milliseconds (N=7,451) |
Baseline PR >200 milliseconds (N=124) |
|---|---|---|---|
| Age, years | 46 ± 15 | 46 ± 15 | 55 ± 16 |
| Female sex, n (%) | 4089 (54) | 4055 (54) | 34 (27) |
| Body mass index, kg/m2 | 25.8 ± 4.3 | 25.8 ± 4.3 | 26.6 ± 3.4 |
| Cigarette smoking, n (%) | 3417 (45) | 3365 (45) | 52 (42) |
| Hypertension, n (%) | 2462 (33) | 2409 (32) | 53 (43) |
| Diabetes mellitus, n (%) | 661 (9) | 637 (9) | 24 (19) |
| Total/HDL cholesterol ratio | 4.4 ± 1.6 | 4.4 ± 1.6 | 4.6 ± 1.7 |
| Valve disease, n (%) | 432 (6) | 418 (6) | 14 (11) |
| Prior MI or CHF, n (%) | 169 (2) | 157 (2) | 12 (10) |
| Heart rate, beats/min | 76 ± 14 | 76 ± 14 | 65 ± 12 |
| ECG-LVH, n (%) | 69 (1) | 67 (1) | 2 (2) |
| Atrial premature beats, n (%) | 76 (1) | 75 (1) | 1 (1) |
| Mean QRS, milliseconds | 87 ± 10 | 87 ± 10 | 93 ± 16 |
| Mean PR, milliseconds | 151 ± 20 | 150 ± 19 | 216 ± 15 |
| Median PR, milliseconds | 149 | 149 | 211 |
Values shown are mean ± SD, medians, or numbers (percents). CHF, congestive heart failure; ECG-LVH, electrocardiographic left ventricular hypertrophy; MI, myocardial infarction. The presence of atrial premature beats is defined based on a 10-second rhythm strip.