Table 1. Baseline Characteristics of the Study Population Table 1. Baseline Characteristics of the Study Population Table 1. Baseline Characteristics of the Study Population Table 1. Baseline Characteristics of the Study Population Table 1. Baseline Characteristics of the Study Population
Characteristics Normal PR interval (N=5716) Normal PR interval (N=5716) Prolonged PR interval (N=472) Prolonged PR interval (N=472) Prolonged PR interval (N=472) P-value
QRS axis >37° QRS axis ≤37° QRS axis >37° QRS axis >37° QRS axis ≤37°
(N=2891) (N=2825) (N=183) (N=183) (N=289)
Age, yrs 55.1±12.2 60.0±13.1 60.1±13.1 60.1±13.1 67.8±13.3 <0.001
Female sex, % 1672 (57.8) 1534 (54.3) 79 (43.2) 79 (43.2) 119 (41.2) <0.001
White, % 2104 (72.8) 2046 (72.4) 113 (61.7) 113 (61.7) 201 (69.6) 0.009
Total annual income <$20K, % 1181 (41.5) 1345 (48.5) 74 (40.9) 74 (40.9) 139 (49.6) <0.001
Current smoke, % 797 (27.6) 511 (18.1) 55 (30.1) 55 (30.1) 40 (13.8) <0.001
Body mass index, kg/m2 26.6±5.4 28.5±5.4 27.1±5.7 27.1±5.7 29.1±5.8 <0.001
Diabetes mellitus, % 214 (7.4) 353 (12.5) 16 (8.7) 16 (8.7) 35 (12.1) <0.001
History of CVD†, % 384 (13.5) 297 (10.7) 21 (11.6) 21 (11.6) 28 (10.0) 0.007
Antihypertensive medications use, % 539 (18.8) 888 (31.5) 67 (36.6) 67 (36.6) 131 (45.6) <0.001
Cancer, % 247 (8.5) 283 (10.0) 18 (9.8) 18 (9.8) 53 (18.3) <0.001
AV nodal drug use‡, % 134 (4.6) 186 (6.6) 21 (11.5) 21 (11.5) 36 (12.5) <0.001
HDL-c§, mg/dL 52.7±16.5 50.6±16.2 51.7±17.9 51.7±17.9 49.9±16.1 <0.001
Diastolic blood pressure, mmHg 76.8±11.7 79.0±12.2 77.1±13.8 77.1±13.8 76.3±12.7 <0.001
Systolic blood pressure, mmHg 129.2±19.9 136.2±20.2 132.8±20.1 132.8±20.1 138.4±21.9 <0.001
Corrected QT interval, ms 428.7±22.7 432.2±23.6 423.6±25.0 423.6±25.0 425.7±25.5 <0.001
Heart rate, bpm 68.9±11.2 68.7±11.5 65.0±10.0 65.0±10.0 63.9±11.4 <0.001
PR interval, ms 156.4±21.6 159.7±20.3 215.3±14.3 215.3±14.3 220.0±20.6 <0.001
QRS duration, ms 94.6±9.8 95.7±9.7 95.5±10.9 95.5±10.9 96.1±10.6 <0.001
P-wave duration, ms 108.6±12.8 111.7±13.5 123.7±14.4 123.7±14.4 127.9±15.9 <0.001
Negative P-wave V1, uV -33.0 [-51.0, -18.0] -39.0 [-55.0, -24.0] -41.0 [-60.0, -27.0] -41.0 [-60.0, -27.0] -48.0 [-64.0, -33.0] <0.001
P-wave axis, ° 67.0 [53.0, 77.0] 59.0 [44.0, 70.0] 66.0 [48.5, 77.0] 66.0 [48.5, 77.0] 55.0 [41.0, 68.0] <0.001
QRS axis, ° 60.0 [49.0, 73.0] 12.0 [-6.0, 25.0] 60.0 [49.5, 72.0] 60.0 [49.5, 72.0] 5.0 [-11.0, 22.0] <0.001
Values are expressed as mean ± SD, N (%) or median values [first quartile, third quartile]. Values are expressed as mean ± SD, N (%) or median values [first quartile, third quartile]. Values are expressed as mean ± SD, N (%) or median values [first quartile, third quartile]. Values are expressed as mean ± SD, N (%) or median values [first quartile, third quartile]. Values are expressed as mean ± SD, N (%) or median values [first quartile, third quartile]. Values are expressed as mean ± SD, N (%) or median values [first quartile, third quartile]. Values are expressed as mean ± SD, N (%) or median values [first quartile, third quartile]. Values are expressed as mean ± SD, N (%) or median values [first quartile, third quartile].
†CVD: cardiovascular disease; ‡AV nodal drug use: β-blocker or Dihydropyridine calcium blocker; §HDL-c: high-density lipoprotein cholesterol. †CVD: cardiovascular disease; ‡AV nodal drug use: β-blocker or Dihydropyridine calcium blocker; §HDL-c: high-density lipoprotein cholesterol. †CVD: cardiovascular disease; ‡AV nodal drug use: β-blocker or Dihydropyridine calcium blocker; §HDL-c: high-density lipoprotein cholesterol. †CVD: cardiovascular disease; ‡AV nodal drug use: β-blocker or Dihydropyridine calcium blocker; §HDL-c: high-density lipoprotein cholesterol. †CVD: cardiovascular disease; ‡AV nodal drug use: β-blocker or Dihydropyridine calcium blocker; §HDL-c: high-density lipoprotein cholesterol. †CVD: cardiovascular disease; ‡AV nodal drug use: β-blocker or Dihydropyridine calcium blocker; §HDL-c: high-density lipoprotein cholesterol. †CVD: cardiovascular disease; ‡AV nodal drug use: β-blocker or Dihydropyridine calcium blocker; §HDL-c: high-density lipoprotein cholesterol. †CVD: cardiovascular disease; ‡AV nodal drug use: β-blocker or Dihydropyridine calcium blocker; §HDL-c: high-density lipoprotein cholesterol.