Myocardial contractile reserve: a global approach by combining cardiopulmonary exercise test with exercise-echocardiography

Purpose: several approaches are available to evaluate myocardial contractile reserve during exercise. Cardiopulmonary exercise test (CPET) allows a response characterization by well established variables with powerful prognostic power. Echocardiography allows for peak cardiac power output (CPO= mean BP x (SV/60) x HR) calculation, by incorporating flow measurement with blood pressure, which has been proposed as an index of energy imparted by the left ventricle (LV) to the volume of blood ejected per second. We aimed to explore if CPO reflects functional capacity as evaluated by CPET. Methods: 108 patients with different cardiovascular disease (HFrEF 37%, HFpEF 63%, aortic and mitral valvular disease 2.8% , aortic valvular disease 11.1%, mitral valvular disease 21.3%, mean age 63\ub113; male 60%; NYHA class II 50%, III 42% and IV 8%, , mean EF 52\ub115%) were evaluated at rest and during incremental exercise (tiltable cycle ergometer) assessing CPO, peak VO2, % of predicted peak VO2 and peak O2 pulse. Results: a good linear correlation was found between CPO and peak VO2, % of predicted peak VO2 and peak O2 pulse (Sperman\u2019s rho respectively of 0.570, 0.692 and 0.620, p 640,0001). The correlation was maintained along all the spectrum of LV systolic function at rest (see the figure), being patients with reduced EF (n 40) distributed on the left-side of the regression due to the reduced contractile reserve. Conclusions: CPET indices of functional capacity showed a good correlation with echo-derived CPO, both in normal and reduced LV systolic function. These results confirm the potential prognostic role of such echocardiographic index and suggest the importance of systematically assess CPO during stress echocardiography