Table 1.
Baseline characteristics of patients, and correlations with baseline heart rate and chronotropic index
| Characteristic | n | Median (25th, 75th) | Spearman correlation with baseline resting heart rate | Spearman correlation with baseline chronotropic index |
|---|---|---|---|---|
| Age, years | 1118 | 57 (49–65) | −0.22 | 0.01 |
| BMI, kg/m2 | 1117 | 31 (26–36) | 0.15 | −0.08 |
| LVEF, % | 1115 | 25 (21–31) | −0.13 | 0.06 |
| BUN, mg/dL | 952 | 19 (14–25) | −0.13 | −0.14 |
| Creatinine, mg/dL | 984 | 1.1 (0.9–1.4) | −0.14 | −0.16 |
| ACE-I dose, mg/day | 1094 | 20 (4–40) | −0.01 | −0.01 |
| Beta-Blocker dose, mg/day | 1109 | 50 (25–50) | −0.05 | −0.16 |
| Loop diuretic dose, mg/day | 1101 | 40 (0–80) | 0.11 | −0.22 |
| Peak VO2, mL/kg/min | 1090 | 15.0 (11.8–18.3) | −0.06 | 0.45 |
| Peak respiratory exchange ratio | 1083 | 1.09 (1.02–1.15) | −0.07 | 0.23 |
| Ve/VCO2 slope | 1082 | 31.6 (27.6–36.3) | 0.04 | −0.13 |
| CPX duration, min | 1104 | 10.0 (7.4–12.7) | −0.11 | 0.48 |
| Six-minute walk distance, m | 1093 | 377 (305–440) | −0.08 | 0.30 |
| Resting heart rate (b.p.m.), CPX test | 1118 | 70 (62–79) | – | 0.09 |
| Chronotropic index | 1118 | 0.56 (0.42–0.71) | 0.09 | – |
| Keteyian chronotropic index | 1112 | 0.93 (0.71–1.19) | 0.05 | 0.99 |
BMI, body max index; LVEF, left ventricular ejection fraction; BUN, blood urea nitrogen; ACE-I, angiotensin-converting enzyme-inhibitors.