The document discusses the use of cardiopulmonary exercise testing (CPET) in evaluating functional capacity in patients with mitral regurgitation, focusing on various CPET parameters such as VO2 max, O2 pulse, and ventilatory efficiency. It highlights correlations between exercise performance and mitral regurgitation severity, noting that impaired ventilatory efficiency is significant in patients with severe conditions. The study emphasizes the importance of rehabilitation in managing these patients.

1. Cardiopulmonary
Exercise Testing in Mitral
Regurgitation
Dr Koh Choong Hou
Mar 2019

2. Scope
• CPET parameters
• Mitral Regurgitation
★ Combination and correlation with echo in FMR
★ Functional capacity assessment
★ Pre and Post mitral repair

3. CPET Parameters

5. CPET Parameters
• VO2 Max
‣ Maximal oxygen extraction as a function of cardiorespiratory performance
‣ (HRmax x SVmax) x (CaO2max - CvO2min)
• O2 Pulse
‣ Amount of oxygen consumed (“O2”) from the volume of blood delivered to
the tissue per heartbeat (“pulse”); alternatively defined as the volume of O2
ejected from the LV in each beat
‣ Since oxygen extraction is maximal and constant at peak exercise, O2 pulse
= surrogate of SV
‣ Diminished in severe LV dysfunction or VHD

6. CPET Parameters
• VE/VCO2
‣ “Ventilatory equivalent for CO2”
‣ Reflection of ventilatory efficiency (“what controls respiration”): chemoreceptor sensitivity,
acid-base balance, ventilatory efficiency at alveolar-alveolar-capillary interface
‣ Increased in pulmonary disease or HF
๏ Exercise starts: VE/VCO2 drops (improved V/Q matching)
๏ Mid exercise: VE/VCO2 constant
๏ Exercise peaks: VE/VCO2 small increases (lactic acidosis stimulates VE)

7. CPET Parameters
• Anaerobic Threshold
‣ Highest VO2 achieved without sustained
increase in blood lactate concentration or
lactate-pyruvate ratio
‣ In healthy population, usually occurs at 47 -
64% of VO2max

8. CPET Parameters
• Respiratory Exchange Ratio (RER)
‣ VCO2/VO2
‣ Represents metabolic exchange of gases at tissue level and
dependent on predominant fuel (cbh vs fat) used for metabolism
‣ Objective means of quantifying effort
✓ 1 to 1.1 = fair effort
✓ 1.1 to 1.2 = good effort
✓ >1.2 = excellent effort

10. Mitral Regurgitation

12. Dynamic / Functional MR during exercise
(baseline HFrEF)
*VO2, O2 pulse, VE/VCO2

14. Key features
• Inclusion: chronic heart failure with LV dilation (indexed end
diastolic volume 80 mL/m2
) and reduced EF (≤40%), capability of
exercise, and adequate transthoracic acoustic windows.
• Exclusion: recent myocardial infarction or acute heart failure (3
months), unstable angina, inducible myocardial ischaemia (or
evidence of papillary muscle ischaemia), aortic stenosis (peak
velocity .3 m/s), peripheral artery disease, significant anaemia
(haemoglobin ,10 g/dL), and respiratory diseases of at least
moderate degree
• 60% ischaemic CMP (with reduced EF)
• CPET performed with tiltable cycle ergometer

16. B: Dynamic MR
A: No MR C: MR @ rest

17. Group B Group C

18. CPET Findings
• All patients had a metabolic maximal exercise (peak RER 1.1)
• Groups B and C had worse exercise performance, as indicated by
lower maximal workload and peak VO2
• Group A patients exhibited a better peak O2 pulse as well as
DVO2/DWR slope
• Lower HRR was found in Group C patients compared with others
• Ventilatory efficiency was severely impaired (VE/VCO2 slope) only
in Group C, while Groups A and B showed similar slight impairment
• Group C compared with Groups A and B showed significantly
increased rest HR, reduced systolic and diastolic pressures at rest and
during exercise

19. B: Dynamic MR
A: No MR C: MR @ rest

21. Correlation of
VE/VCO2 and MR
ERO

23. Key Features
• Inclusion: Pts with organic MR (93% MVP)
1. isolated MR and regurgitant volume quantified by at least 2
methods;
2. quantitative assessment of cardiac remodeling and LV systolic
and diastolic function;
3. performed a maximal exercise test, i.e., achieving their heart
rate goal (􏰆85% of the age-predicted peak heart rate) or
stopped because of symptoms of dyspnea, exhaustion, or
hypotension; and
4. echocardiography and CPET were performed during the same
episode of care without intervening clinical change.

24. Key Features
• Exclusion:
1. age 􏰆>90 years
2. history of congestive heart failure
3. rheumatic mitral stenosis of any degree;
4. moderate or more severe lung disease;
5. exercise limited by angina;
6. exercise testing stopped because of ischemia or severe arrhythmia.

26. Key Findings
• Mitral regurgitation severity
(ERO) is modestly linked to
FC, whereas LV diastolic
dysfunction (high E/e’),
reduced forward stroke volume
and atrial fibrillation
independently and cumulatively
determined FC.
• Peak VO2 >84% as a FC
predictor for
death/HF/AF/mitral Sx

28. Oxygen Uptake
Efficiency Slope
(OUES)
= VE/VO2

30. Key Lesson
• Rehab, rehab, rehab!!

33. The End