Table 3.
Echocardiographic and cardiopulmonary exercise testing parameters by presence or absence of chronotropic incompetence
| Parameter | Chronotropic Incompetence |
P-value | |
|---|---|---|---|
| Absent (n = 27) | Present (n = 81) | ||
| Echocardiography: | |||
| • Left ventricular end-systolic volume (ml/m2) | 30±11 | 31±11 | 0.81 |
| • Left ventricular end-diastolic volume (ml/m2) | 76±17 | 80± 22 | 0.43 |
| • Left ventricular mass index (g/m2) | 90±37 | 105±33 | 0.05 |
| • Left ventricular ejection fraction (% units) | 61±8 | 62±6 | 0.55 |
| • Left atrial volume index (ml/m2) | 32±14 | 32±9 | 0.90 |
| • Ratio of early to late mitral inflow (E/A ratio) | 1.1±0.4 | 1.4±0.7 | 0.04 |
| • Tissue Doppler e' velocity (cm/s) | 7.4±2.6 | 7.2±2.4 | 0.73 |
| • E/e' ratio | 13.8±6.4 | 15.1±6.8 | 0.39 |
| • Diastolic function grade | 0.09 | ||
| ○ Normal diastolic function | 2(7%) | 8(10%) | |
| ○ Grade I (mild) diastolic dysfunction | 4(15%) | 5(6%) | |
| ○ Grade II (moderate) diastolic dysfunction | 13(48%) | 29(36%) | |
| ○ Grade III (severe) diastolic dysfunction | 4(15%) | 32(40%) | |
| ○ Indeterminate diastolic function | 4(15%) | 7(9%) | |
| • Pulmonary artery systolic pressure (mm Hg) | 36±9 | 47±15 | 0.003* |
| Cardiopulmonary exercise testing: | |||
| • Workload (watts) | 85±53 | 67±30 | 0.060 |
| • Exercise time (seconds) | 8.7±3.2 | 7.0±3.1 | 0.019 |
| • Resting heart rate (beats/min) | 77±15 | 70±13 | 0.031 |
| • Resting respiratory rate (breaths/min) | 19±6 | 18±5 | 0.33 |
| • Peak heart rate (beats/min) | 145±12 | 108±21 | < 0.001* |
| • Peak respiratory rate (breaths/min) | 41±9 | 36±8 | 0.015 |
| • Peak systolic blood pressure (mm Hg) | 184±24 | 177±32 | 0.25 |
| • Peak diastolic blood pressure (mm Hg) | 77±14 | 73±14 | 0.18 |
| • Anaerobic threshold | 12±5 | 9.8±2 | 0.001* |
| • Absolute VO2 (L/kg) | 1.5±0.6 | 1.2±0.4 | 0.005 |
| • Relative VO2 (ml/kg/min) | 18±7 | 13±4 | < 0.001* |
| • Oxygen pulse (mL/beat) | 10±4 | 11±4 | 0.25 |
| • Peak VE (L/min) | 62±25 | 46±14 | < 0.001* |
| • VE/VCO2 ratio at anaerobic threshold | 33±5 | 32±4 | 0.32 |
| • Breathing reserve | 26±14 | 31±19 | 0.15 |
| • Respiratory exchange ratio | 1.2±0.1 | 1.2±0.1 | 0.12 |
| • HR recovery at 1 min (beats/min) | 26±2 | 16±1 | < 0.001* |
| • HR recovery at 2 min (beats/min) | 40±3 | 25±2 | < 0.001* |
VE = ventilatory equivalents; VO2 = maximal oxygen consumption; VCO2 = maximal carbon dioxide output
Values expressed as mean ± standard deviation, unless otherwise specified
*
Statistically significant (q < 0.05) after adjustment for false discovery rate