Introduction
Methodology of CPET
CPET variables interpretation
Variables | Meaning | Normal values |
---|---|---|
Peak VO2 | Highest oxygen uptake (aerobic capacity) | > 85% of predicted Varies with age sex activity level, weight, use of betablockers |
Ventilatory threshold (VT) | Represents the moment at which anaerobic metabolism increases (aerobic-anaerobic switch) | Between 40 to 60% of peak VO2 |
Ventilatory volume/carbon dioxide output (VE/VCO2) slope | Corresponds to ventilatory efficiency | Between 25 and 30 |
Peak respiratory exchange ratio (VCO2/VO2) | Reflects metabolism | < 0.8 at rest > 1.1 physiological maximal effort |
Peak Heart rate | Chronotropic competence | Peak rate > 85% of the predicted |
Heart rate recovery | Maximum HR minus HR at 1-min recovery | > 12 bpm |
End-tidal PCO2 | Identifies the perfusion state | > 33 mmHg at rest > 36 mmHg during exercise |
O2 uptake efficiency slope | Additional logarithmic model of ventilatoryefficiency | < 1.4 |
Peak VE/Maximal voluntary ventilation (MVV) | Reflects the ventilatory reserve | 15–20% |
Clinical applications
Exercise prescription
CPET in heart failure
Variable | Value | Points |
---|---|---|
VE/VCO2slope | ≥34 | 7 |
HR recovery | ≤6 | 5a |
O2 uptake efficiency slope | ≤1.4 | 2 |
Peak VO2 | < 14 mL/Kg/min | 2 |
CPET in differential diagnosis of dyspnoea
Condition | Variables |
---|---|
Cardiovascular | Peak VO2 < 80% of the predicted |
Low ventilatory threshold (VT) | |
Chronotropic incompetence | |
Heart rate recovery ≤12 BPM after the first minute | |
Pulmonary | Peak VO2 < 80% of the predicted |
Low ventilatory threshold (VT) | |
Peak respiratory rate > 50/min | |
Ventilatory reserve (peak VE/MVV) < 15% | |
Oxygen desaturation | |
Deconditioning | Low-normal peak VO2 |
Low ventilatory threshold (VT) | |
Absence of any other abnormal response | |
Obesity | Absolute VO2 greater than predicted |
Indexed peak VO2 lower than predicted | |
Increased VO2/work slope | |
Muscle disease | Submaximal cardiac and respiratory response |
Low ventilatory threshold (VT) | |
Elevate lactate at submaximal work |
CPET in congenital heart disease
Integration of CPET and echocardiography
Heart failure
Valvular heart disease
Primary cardiomyopathies
Pulmonary arterial hypertension
Coronary artery disease
Variables | Meaning | Normal values |
---|---|---|
Δ LVEF | Contractile reserve | > 5% |
ΔGLS | Contractile reserve | > 2% |
ΔSV | Contractile reserve | > 20% |
Peak E/e’ | Elevated LV filling pressure during stress | > 15 |
Peak PAPs | Maximal pulmonary systolic pressure during stress | > 60 mmHg |
ΔEROA | Changes in mitral regurgitation severity during time | < 10 mm3 |
ΔTransmitral MPG | Changes in transmitral pressure gradient during stress | < 15 mmHg |
ΔTransaortic MPG | Changes in transaortic pressure gradient during stress | < 20 mmHg |
LVOT Maximal Peak Gradient | In case of LVOT obstruction it reflects pathological | < 50 mmHg – low prognostic impact |