Characteristics of patients with and without chronotropic incompetence (CI)
| Characteristic | Total | CI group | No CI group | p-value |
|---|---|---|---|---|
| No. of patients | 111 | 45 | 66 | |
| Age (yr) | 16.2±1.8 | 15.9±2.1 | 16.3±1.6 | 0.186 |
| Male sex | 61 (55.0) | 26 (57.8) | 35 (53.0) | 0.625 |
| Body mass index (kg/m2) | 20.6±3.5 | 20.5±3.3 | 20.7±3.8 | 0.829 |
| Birth weight (kg) | 3.0±0.5 | 2.9±0.5 | 3.1±0.5 | 0.174 |
| Cyanosis | 19 (17.1) | 13 (28.9) | 6 (9.1) | 0.012 |
| No. of surgical procedures | 2.6±1.6 | 3.9±1.9 | 2.1±1.1 | <0.001 |
| No. of medications | 1.43±1.8 | 2.2±2.1 | 0.9±1.2 | <0.001 |
| Rest SaO2 (%) | 97.3±3.2 | 97.1±3.3 | 97.5±3.1 | 0.572 |
| Rest HR (beats/min) | 75.5±13.9 | 78.0±16.1 | 73.8±12.0 | 0.136 |
| Peak HR (beats/min) | 180.0±19.2 | 161.8±15.4 | 192.4±8.8 | <0.001 |
| HR reserve (beats/min) | 104.5±22.1 | 83.7±16.6 | 118.7±11.8 | <0.001 |
| Rest SBP (mm Hg) | 119.8±18.7 | 113.9±18.2 | 123.9±18.0 | 0.005 |
| Rest DBP (mm Hg) | 70.6±12.8 | 65.9±9.7 | 73.8±13.6 | 0.001 |
| Peak SBP (mm Hg) | 144.6±21.7 | 141.2±23.9 | 146.9±19.8 | 0.194 |
| Peak DBP (mm Hg) | 66.1±13.5 | 65.5±16.0 | 66.4±11.7 | 0.738 |
| Peak O2 pulse (mL/beat) | 9.7±5.6 | 9.2±4.6 | 10.0±6.1 | 0.773 |
| Peak VO2 (mL/kg/min) | 31.5±8.2 | 27.3±7.3 | 34.4±7.6 | <0.001 |
| RER | 1.13±0.11 | 1.09±0.10 | 1.15±0.10 | 0.002 |
| RPE | 16.9±1.4 | 16.8±1.8 | 17.0±1.2 | 0.545 |
| Physical activity (METs-hr/wk) | 16.0 (10.0−30.0) | 10.7 (7.3−16.3) | 22.8 (11.5−36.7) | <0.001 |
Values are presented as number only, mean±standard deviation, number (%), or median (interquartile range).
SaO2: oxygen saturation, HR: heart rate, SBP: systolic blood pressure, DBP: diastolic blood pressure, O2 pulse: oxygen pulse, VO2: oxygen uptake, RER: respiratory exchange ratio, RPE: ratings of perceived exertion, MET: metabolic equivalent.
