Introduction: Quantitative stress echocardiography provides sensitive markers for diagnosing subendocardial dysfunction but its specifity is low. (1, 2) We combine exercise gas exchange measurements with quantitative stress echocardiography in order to better distinguish between ischemic and non-ischemic causes of myocardial dysfunction.

Patients and Methods: We describe the method of the cardiopulmonary echocardiographic exercise test (CPEET) and provide examples that differentiate between ischemic and non-ischemic substrates. In 35 patients, we correlated peak strain rate, peak systolic myocardial velocity, and peak left ventricular filling pattern with gas exchange parameters: pVO₂, dVO₂/dWR, pO₂ pulse, AtPETCO₂, and VE/VCO₂ slope during exercise test. Statistical analysis was performed using SPSS Statistics for Windows version 25. The values of p < 0.05 were considered statistically significant.

Results: Peak strain rate correlates positively with pVO₂, AtVO₂, dVO₂/dWR, pO₂ pulse, AtPETCO₂ and negatively with VE/VCO₂ slope. pVs correlates positively with pVO₂, AtVO₂, O₂ pulse, dVO₂/dWR, AtPETCO₂, and negatively with VE/VCO₂ slope. Correlation of pSR with pV02 and dV02/dWR is stronger than correlation of Vs, respectively. pE/e ratio correlates negatively with pVO₂, AtVO₂, PETCO₂ and positively with VE/VCO₂ slope.

Conclusion: Combining pSR/pVs with peak VO₂, dVO₂/dWR, and peak oxygen pulse may better distinguish ischemic from non-ischemic substrate. Additionally, other exercise gas exchange parameters combined with stress echo-derived metrics could enhance the diagnosis of pathophysiological conditions, such as reduced exercise peak VO₂ and reduced SR/Vs.