Table 1.
Baseline Characteristics of the Study Population
| Characteristics | Total (n=285 194) | Women | Men | ||||
|---|---|---|---|---|---|---|---|
| All (n=160 879) | Age <65 (n=115 651) | Age ≥65 (n=45 097) | All (n=124 315) | Age <65 (n=100 616) | Age ≥65 (n=23 699) | ||
| Age—y, median (IQR) | 53 (41 to 65) | 54 (40 to 67) | 47 (36 to 56) | 75 (70 to 81) | 54 (40 to 62) | 47 (37 to 56) | 72 (68 to 78) |
| Medical history—no. (%) | |||||||
| Congestive heart failure | 1113 (0.4) | 742 (0.5) | 131 (0.1) | 611 (1) | 371 (0.3) | 112 (0.1) | 259 (1) |
| Valvular heart disease | 702 (0.2) | 426 (0.3) | 166 (0.1) | 260 (0.6) | 276 (0.2) | 150 (0.2) | 126 (1) |
| Modified Charlson co‐morbidity index | |||||||
| 0 points | 236 699 (83) | 131 413 (80) | 100 603 (87) | 30 810 (68) | 105 286 (85) | 88 962 (88) | 16 324 (69) |
| 1 point | 27 705 (10) | 16 408 (10) | 9314 (8) | 7094 (16) | 11 297 (9) | 7682 (8) | 3615 (15) |
| ≥2 points | 20 790 (7) | 13 058 (8) | 5865 (5) | 7193 (16) | 7732 (6) | 3972 (4) | 3760 (16) |
| Medication history—no. (%) | |||||||
| ACE inhibitors | 34 610 (12) | 20 168 (13) | 9465 (8) | 10 703 (24) | 14 442 (12) | 9122 (9) | 5320 (23) |
| Beta‐blockers | 34 489 (12) | 23 571 (15) | 14 526 (13) | 9045 (20) | 10 918 (9) | 7490 (7) | 3428 (14) |
| Calcium‐antagonists | 27 946 (10) | 16 951 (11) | 6999 (6) | 9952 (22) | 10 995 (9) | 6435 (6) | 4542 (19) |
| Non‐loop diuretics | 59 466 (21) | 42 967 (27) | 21 029 (18) | 21 938 (48) | 16 499 (13) | 9067 (9) | 7432 (31) |
| ECG variables | |||||||
| Heart rate—bpm, median (IQR) | 69 (62 to 78) | 71 (63 to 79) | 70 (62 to 78) | 73 (65 to 82) | 67 (60 to 77) | 67 (59 to 76) | 69 (61 to 80) |
| Left ventricular hypertrophy—no. (%) | 12 286 (4) | 3509 (2) | 1737 (2) | 1772 (4) | 8777 (7) | 7371 (7) | 1406 (6) |
| QRS duration—ms, median (IQR) | 92 (86 to 100) | 88 (82 to 94) | 88 (84 to 94) | 88 (82 to 94) | 98 (90 to 104) | 98 (92 to 104) | 96 (88 to 102) |
| Subjects in ECG reference range (−50 to +50 μV)—no. (%) | |||||||
| V1 | 196 654 (69) | 122 242 (76) | 90 909 (79) | 31 333 (70) | 74 412 (60) | 59 524 (59) | 14 888 (63) |
| V2 | 68 332 (24) | 52 482 (33) | 32 994 (29) | 19 488 (43) | 15 850 (13) | 9433 (9) | 6417 (28) |
| V3 | 105 227 (37) | 83 130 (52) | 57 143 (49) | 25 987 (58) | 22 097 (18) | 13 614 (14) | 8483 (36) |
| V4 | 178 139 (63) | 130 603 (81) | 93 539 (81) | 37 064 (83) | 47 536 (38) | 32 780 (33) | 14 756 (67) |
| V5 | 224 851 (79) | 146 434 (91) | 106 387 (92) | 40 047 (89) | 78 417 (63) | 59 442 (59) | 18 975 (81) |
| V6 | 254 266 (89) | 152 797 (95) | 111 296 (96) | 41 501 (92) | 101 469 (82) | 80 563 (80) | 20 906 (89) |
bpm indicates beats per minute; IQR, inter‐quartile range; ms, milliseconds.