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

Exercise gas exchange patterns in diabetes : evidence from the EURO(pean) EX(ercise) population-based study

Introduction: Diabetes mellitus (DM) is a risk condition that may determine exercise limitation and reduced oxygen consumption (VO2). Hypothesis: No study in literature has addressed the cardiopulmonary exercise testing (CPET) phenotype in diabetic subjects with normal left ventricular function. Their functional characterization by expired gas analysis may help to better define cardiovascular (CV) risk and to improve the timing of therapeutic interventions. Methods: 442 asymptomatic subjects enrolled in the EURO EX trial, (mean age 60\ub114 years; male 49.3%; BMI 28\ub15.5 kg/m2) with different CV risk factors (hypertension 66%, dyslipidemia 50.2%, smoking habit 19.2%, diabetes 15.4%) underwent a maximal CPET with personalized ramp protocol. Results: The population was divided into two groups according to the presence of diabetes. Diabetic subjects (n=68) were significantly older than non-DM subjects and showed a significant lower VO2 at peak exercise (16.3\ub14.1 vs 19.9\ub17.4 ml/kg/min), a steeper VE/VCO2 slope (27\ub13.7 vs 25.7\ub14) and an impaired heart rarte reserve (peak HR 123\ub127 vs 135\ub122 bpm) and recovery (HRR 12\ub16 vs 17\ub111 beats) and higher systolic blood pressure (SBP) at rest (142\ub122 vs 132\ub115 mmHg) and peak exercise (193\ub120 vs 184\ub122 mmHg). A significant difference in the VE/VCO2 slope, peak O2 pulse, SBP at rest and \u394VO2/\u394WR slope was maintained when a correction for confounding factors (BMI, age, gender, prevalence of dyslipidemia and hypertension) was applied. Conclusions: Asymptomatic DM subjects with normal left ventricular function compared to non-diabetics show a reduced HRR and peak O2 pulse, an increased VE/VCO2 slope and higher SBP as a typical phenotype. These findings suggest that an impaired sympathovagal control may play a key role. Whether assessment of these variables may improve the risk-related definition and a timely metabolic control in this patients seems to be worth of further investigation

mpaired gas diffusion and RV to pulmonary circulation uncoupling limit exercise performance in heart failure patients

Introduction: In heart failure (HF) patients, an altered gasdiffusing capacity for carbon monoxide (DLCO) is a marker of lung capillary injury that bears relevant clinical and prognostic information. It is unknown whether right heart-pulmonary circulation (RH-PC) uncoupling abnormalities and gas diffusion are linked and may become synergic in causing exercise limitation and ventilation inefficiency. Methods: 17 HF patients (mean age 64\ub111; male 75%; NYHA II-III; mean left ventricular (LV) ejection fraction 34\ub19%) underwent DLCO measurements with assessment of membrane component (DM) an capillary blood volume (Vc) and underwent to maximal cardiopulmonary exercise testing (CPET, tilt-ergometer,personalized ramp protocol) combined with Echo-Doppler assessment of right ventricular function by assessing tricuspid annular peak systolic excursion (TAPSE) and pulmonary systolic pressure (PASP). Results: Patients exhibited an abnormal gas diffusion (mean DLCO 17\ub13.9 ml/min/mmHg) with depressed alveolar-capillary membrane diffusing capacity (DM) component (mean 23.4\ub16.8 ml/min/mmHg) and elevated capillary volume (mean 111.2\ub164 ml) along with significant functional limitation (mean peak VO2 12.5\ub13.7 ml/kg/min) and ventilatory inefficiency(mean VE/VCO2 slope: 34.4\ub16.9 and mean end-tidal of CO2 mean 32.1\ub15.2 mmHg). Significant correlations were found between DM, TAPSE/PASP relationship, peak VO2 and VE/VCO2 slope at peak exercise (figure). Conclusions: Our findings show a link between the RV-PC uncoupling with gas diffusion abnormalities suggesting that interventions aimed at targeting the functional performance in HF population have to ideally combine amodulatory effect on both the alveolar-capillary gas diffusion capacity and right heart function

Severity of functional mitral regurgitation during maximal exercise testing in heart failure: additional value of combining echocardiography with cardiopulmonary exercise testing

Background: In heart failure (HF) patients the severity of mitral regurgitation (MR) at rest has a well established prognostic value and its increase during exercise further adds to an increased risk. Our goal was to define the relationship between the degree of exercise MR severity with cardiopulmonary and echocardiographic related phenotypes in a cohort of HF patients. Methods: 71 HF reduced ejection fraction patients (mean age 67\ub111; male 72%; ischemic etiology 61%; NYHA class I, II, III and IV 13%, 36%, 39% and 12%, mean ejection fraction 33\ub19%) underwent cardiopulmonary exercise test (CPET) on tiltable cycle-ergometer combined with echocardiography at rest and during exercise. The population was divided into two groups according to the degree of functional peak MR: no to mild/moderate MR (no MR, MR1+ and MR2+) vs moderate/severe MR (MR3+ and MR4+). Results: A good correlation (\u3c1 coefficient= 0.49) was found between the degree of dynamic MR and PASP at peak exercise. Despite similar echocardiographic profile at rest patients with significant peak MR (MR 653+) had worse exercise performance (lower peak VO2, O2 pulse and workload) and impaired ventilatory efficiency (higher VE/VCO2 slope). Conclusions: In HF patients the severity of exercise-induced MR is associated with the most unfavorable performance and pulmonary hemodynamic response. A combined approach with CPET and echocardiographic assessment can help to early unmask and target functional MR and its related unfavorable phenotypes

Oxygen uptake EF : insights from exercise-echocardiography

Background: Cardiopulmonary exercise test (CPET) allows functional assessment by assessing VO2 and its kinetic. The flattening of VO2/WR slope during incremental maximal exercise has been described in some cardiovascular disorders, mainly in heart failure (HF) patients with reduced EF (HFrEF) and in the presence of exercise-induced myocardial ischemia. In a HFrEF population we explored the cardiac determinants of VO2/WR looking at both systolic and diastolic HF. Methods and Results: 39 HFrEF patients (mean age 63\ub19; male 70%; NYHA II 47%, III 45%, IV 8%) underwent a maximal cardiopulmonary exercise testing evaluation (bike, personalized incremental ramp protocol) combined with Echo-Doppler assessment. We considered 2 subgroups according to the occurrence of VO2/WR slope flattening, defined as a change >20% of the slope during exercise (mean LVEF at rest 33\ub17%, at peak exercise 35\ub110%; mean RV Area Fraction at rest 40\ub113%, at peak exercise 30\ub113%; without significant difference between the 2 subgroups). The table shows the main clinical characteristics and test results. Conclusions: In this HFrEF population VO2/WR slope flattening is significantly associated with higher NTproBNP serum levels, more severe dilatation of both ventricles and left atrium at rest and peak exercise, a more severe mitral regurgitation at rest and peak exercise and a lower peak O2 pulse. These results highlight the relevance of detecting a VO2/WR flattening as a marker for identifying a subset of HFrEF patients with a more compromised global cardiac function during exercise