Table 1.
Baseline Characteristics of the Study Population by Heart Rate Quintile
| Characteristic | Heart Rate |
P value |
||||
|---|---|---|---|---|---|---|
| 30–55 bpm n =1010) |
56–60 bpm (n = 1006) |
61–66 bpm (n = 1173) |
67–72 bpm (n = 1009) |
73–118 bpm (n = 1063) |
||
| Age, median (IQR), y | 58.3 (46.9–66.1) | 55.8 (44.8–65.5) | 54.2 (45.0–64.0) | 54.7 (45.3–64.1) | 55.8 (45.6–64.8) | .001 |
| Men, No. (%) | 46.5 | 40.7 | 33.4 | 30.7 | 32.0 | < .001 |
| Medical history, No. (%) | ||||||
| Chronic lung disease | 5.3 | 6.0 | 6.9 | 7.3 | 10.3 | < .001 |
| Diabetes mellitus | 13.4 | 16.7 | 18.6 | 22.4 | 37.4 | < .001 |
| Heart failure | 5.8 | 5.3 | 6.0 | 7.7 | 11.9 | < .001 |
| Hypertension | 56.6 | 57.3 | 57.0 | 60.1 | 69.1 | < .001 |
| Myocardial infarction | 6.0 | 6.4 | 4.9 | 3.9 | 6.0 | .07 |
| Stroke | 3.7 | 4.2 | 4.3 | 5.1 | 4.4 | .66 |
| Current smoker | 13.6 | 13.0 | 12.1 | 13.3 | 13.4 | .86 |
| Prior smoker | 21.4 | 19.8 | 18.6 | 16.7 | 19.8 | .10 |
| Weekly hours of physical activity, No. (%) | .001 | |||||
| 0 | 44.5 | 45.5 | 45.8 | 50.3 | 52.8 | < .001 |
| < 1 | 9.8 | 10.8 | 11.8 | 10.4 | 9.1 | .28 |
| 1 to < 2 | 16.4 | 17.7 | 15.3 | 16.7 | 15.9 | .65 |
| 2 to < 3 | 7.6 | 7.7 | 9.0 | 8.2 | 7.6 | .68 |
| 3 to < 4 | 8.0 | 6.3 | 6.6 | 4.4 | 5.7 | .01 |
| ≥ 4 | 13.7 | 12.0 | 11.3 | 9.9 | 8.8 | .006 |
| Caffeine consumption, median (IQR), mg/d | 85.5 (20.9–186.0) | 83.2 (24.3–187.3) | 80.7 (20.1–180.7) | 83.2 (24.3–184.9) | 83.2 (20.6–182.9) | .57 |
| Physical examination, median (IQR) | ||||||
| Body mass index, kg/m2 | 29.2 (26.1–33.7) | 29.6 (26.2–34.2) | 30.3 (27.0–35.1) | 31.3 (27.1–36.1) | 32.4 (28.1–38.3) | < .001 |
| Systolic blood pressure, mm Hg | 124.0 (114.0–136.0) | 124.0 (113.0–136.0) | 125.0 (114.0–137.0) | 125.0 (115.0–136.0) | 127.0 (116.0–140.0) | < .001 |
| Laboratory test results | ||||||
| Sodium, mEq/L | 141.0 (139.0–142.0) | 141.0 (139.0–142.0) | 141.0 (139.0–142.0) | 140.0 (139.0–142.0) | 141.0 (139.0–142.0) | .01 |
| eGFR, mL/min/1.73 m2 | 84.5 (73.5–94.1) | 85.6 (75.8–94.6) | 85.8 (76.8–95.6) | 87.3 (76.9–98.5) | 87.7 (75.4–100.9) | < .001 |
| Hemoglobin, g/dL | 13.1 (12.4–14.1) | 13.0 (12.3–14.0) | 13.0 (12.2–14.0) | 13.0 (12.1–13.8) | 13.0 (12.0–13.8) | < .001 |
| Cardiac test results | ||||||
| Left ventricular ejection fraction, mean (SD), % | 62.3 (7.0) | 62.1 (7.2) | 62.3 (7.2) | 62.0 (7.7) | 61.2 (8.2) | .01 |
| Left ventricular ejection fraction < 40%, No. (%) | 0.7 | 0.8 | 0.5 | 1.3 | 1.3 | .18 |
| Left ventricular hypertrophy, No. (%) | 7.4 | 7.1 | 6.2 | 8.4 | 10.7 | .001 |
| Left ventricular dimension, median (IQR), cm | 49.2 (46.8–52.2) | 48.4 (46.0–51.3) | 48.3 (45.6–50.8) | 48.3 (45.3–50.6) | 47.5 (44.6–50.3) | < .001 |
| Complete LBBB (%) | 1.1 | 1.2 | 0.8 | 0.9 | 0.9 | .87 |
| QRS duration, median, (IQR), msec | 94.0 (86.0–102.0) | 92.0 (84.0–102.0) | 90.0 (84.0–100.0) | 90.0 (84.0–100.0) | 90.0 (84.0–100.0) | < .001 |
| Medications, No. (%) | ||||||
| ACE inhibitor or ARB | 15.0 | 15.3 | 14.5 | 16.8 | 21.7 | < .001 |
| Antiarrhythmic agent | 0.3 | 0.4 | 0.3 | 0.2 | 0.4 | .94 |
| β-Blocker | 16.1 | 12.3 | 7.4 | 7.7 | 6.9 | < .001 |
| Calcium channel blocker | 14.9 | 14.0 | 15.4 | 15.2 | 20.7 | < .001 |
| Digoxin | 1.1 | 1.7 | 0.5 | 1.6 | 2.3 | .008 |
| Diuretic | 22.6 | 21.7 | 19.3 | 22.3 | 29.2 | < .001 |
| Any missing medications | 8.4 | 7.1 | 7.5 | 9.0 | 6.2 | .13 |
Abbreviations: ACE, angiotensin-converting enzyme; ARB, angiotensin II receptor blocker; eGFR, estimated glomerular filtration rate; IQR, interquartile range; LBBB, left bundle-branch block.