Table 1.
Comparison of training and testing, and validation groups
| Characteristics | All (n = 3679) | Training and testing (n = 3068) | Validation (n = 611) |
|---|---|---|---|
| Age (SD), years | 61.6 (11.9) | 61.4 (11.9) | 62.6 (11.6) |
| Male, n (%) | 1332 (36.2) | 1109 (36.2) | 223 (36.5) |
| Weight (SD), kg | 91.2 (21.5) | 91.2 (21.6) | 91.3 (21.5) |
| Height (SD), cm | 168.5 (9.4) | 168.5 (9.4) | 168.6 (9.3) |
| BMI (SD), kg/m2 | 32.1 (7.2) | 32.1 (7.2) | 32.1 (7.4) |
| Obese BMI group, n (%) | 2084 (56.7) | 1738 (56.6) | 346 (56.6) |
| BSA (SD), m2 | 2.00 (0.25) | 2.00 (0.24) | 2.00 (0.23) |
| Ever tobacco smoker, n (%) | 1097 (29.8) | 908 (29.6) | 189 (30.9) |
| Hypertension, n (%) | 2703 (73.5) | 2242 (73.1) | 461 (75.5) |
| Systolic blood pressure (SD), mmHg | 127.6 (18.7) | 127.6 (18.6) | 127.9 (19.0) |
| Diastolic blood pressure (SD), mmHg | 75.0 (10.9) | 75.1 (11.0) | 74.6 (10.3) |
| Heart rate (SD), b.p.m. | 64.0 (10.7) | 64.0 (10.7) | 63.8 (10.6) |
| QRS duration (SD), ms | 89.0 (15.6) | 89.0 (15.7) | 89.1 (15.3) |
| Ventricular conduction defect, n (%) | 27 (0.73) | 17 (0.55) | 10 (1.64) |
| QT interval (SD), ms | 416.5 (30.6) | 416.3 (31.5) | 417.6 (32.9) |
| Bazett corrected QT (SD), ms | 426.7 (25.8) | 426.6 (25.7) | 427.2 (26.3) |
| Framingham corrected QT (SD), ms | 422.2 (22.7) | 422.0 (22.5) | 422.9 (23.5) |
| Hodge corrected QT (SD), ms | 423.5 (23.0) | 423.3 (22.7) | 424.2 (24.4) |
| Fridericia corrected QT (SD), ms | 423.0 (22.1) | 422.9 (22.6) | 423.7 (23.6) |
| Cornell voltage(SD), µV | 1514 (597) | 1507 (593) | 1547 (618) |
| Median beat: normal sinus, n (%) | 3629 (99) | 3026 (98.6) | 603 (98.7) |
| Median beat: atrial fibrillation, n (%) | 36 (1.0) | 13 (0.4) | 1 (0.2) |
| Median beat: ventricular pacing, n (%) | 14 (0.4) | 29 (1.0) | 7 (1.2) |
| QRS area (SD), mV*ms | 38.4 (18.3) | 38.4 (18.3) | 38.7 (18.3) |
| Peak QRS magnitude (SD), mV | 1.59 (0.44) | 1.59 (0.44) | 1.60 (0.45) |
| Area QRS azimuth (95% CI) | 20.9 (20.1–21.6) | 20.7 (19.9–21.6) | 21.5 (19.5–23.4) |
| Peak QRS azimuth (95% CI) | 9.7 (8.9–10.4) | 9.6 (8.8 = 10.4) | 9.8 (8.0–11.7) |
| Area QRS elevation (95% CI) | 73.3 (72.8–73.9) | 73.1 (72.5–73.7) | 74.4 (72.9–75.8) |
| Peak QRS elevation(95%CI) | 72.3 (71.8–72.7) | 72.2 (71.7–72.7) | 72.9 (71.8–74.0) |
| T area (SD), mV*ms | 48.5 (23.1) | 48.5 (22.9) | 48.3 (24.0) |
| Peak T magnitude (SD), mV | 0.36 (0.16) | 0.36 (0.16) | 0.35 (0.16) |
| Area T azimuth (95% CI) | −45.1 (−46.1 to −44.1) | −45.2 (−46.3 to −44.2) | −44.5 (046.8 to −42.2) |
| Peak T azimuth (95% CI) | −36.2 (−37.2 to −35.1) | −36.3 (−37.4 to −35.2) | −35.4 (−37.9 to −33.0) |
| Area T elevation (95% CI) | 75.6 (75.1–76.1) | 75.6 (75.0–76.1) | 76.0 (74.8–77.2) |
| Peak T elevation (95% CI) | 69.9 (69.4–70.4) | 69.9 (69.4–70.4) | 69.8 (68.7–71.0) |
| Area SVG (SD), mV*ms | 69.3 (28.2) | 69.4 (28.2) | 68.7 (28.3) |
| Peak SVG magnitude (SD), mV | 1.81 (0.50) | 1.81 (0.50) | 1.81 (0.50) |
| Area SVG azimuth (95% CI) | −14.0 (−14.7 to −13.3) | −14.1 (−14.9 to −13.3) | −13.3 (−15.1 to −11.5) |
| Peak SVG azimuth (95% CI) | 3.7 (3.0–4.4) | 3.6 (2.9–4.4) | 3.9 (2.2–5.7) |
| Area SVG elevation (95% CI) | 71.5 (71.1–72.0) | 71.3 (70.8–71.9) | 72.6 (71.4–73.9) |
| Peak SVG elevation (95% CI) | 70.8 (70.4–71.2) | 70.7 (70.2–71.1) | 71.4 (70.3–72.5) |
| SAIQRST (SD), mV*ms | 153.9 (51.4) | 153.7 (51.2) | 154.9 (52.6) |
| VM QT integral (SD), mV*ms | 102.9 (34.3) | 102.8 (34.1) | 103.5 (35.4) |
| Area QRS-T angle (95% CI) | 67.1 (66.0–68.3) | 67.1 (65.9–68.3) | 67.2 (64.3–70.0) |
| Peak QRS-T angle (95% CI) | 48.3 (47.2–49.4) | 48.4 (47.2–49.6) | 48.0 (45.2–50.7) |