Multimodal echocardiographic cardiac output assessment during exercise: predictive role for cardiopulmonary performance across heart failure continuum and in healthy subjects
M Maccallini, M Losito, S Rossi, A Tarantino, A Zambon, M GuazziAbstract
Background
Peak oxygen uptake (peak-VO2) reflects the integrated cardiovascular performance and is primarily determined by maximal cardiac output. Three-dimensional echocardiography allows direct volumetric quantification of left ventricular stroke volume without geometric assumptions. However, its physiological capacity for assessing cardiac output at peak exercise (peak-CO) during simultaneous cardiopulmonary exercise test (CPET) has not been investigated.
Purpose
To evaluate the association between peak-VO2 and left ventricular peak-CO derived from three-dimensional echocardiography (3-DE), compared to the conventional two-dimensional echocardiography (2-DE) and Doppler-based methods, across heart failure phenotypes and controls.
Methods
We assessed 126 subjects (46 controls, 46 patients with heart failure with preserved ejection fraction [HFpEF], and 34 with reduced ejection fraction [HFrEF]) undergoing semi-supine cycle CPET imaging by echo. Peak-CO was calculated using 3-DE volumetric datasets, 2-DE methods, and Doppler-based measurements. Associations with peak-VO2 were evaluated overall and by phenotype using Pearson’s product–moment correlation. Multivariable linear regression analysis was performed. The ROC analysis was used for discriminating functional capacity impairment, defined as peak-VO2<18mL/kg/min, comparing peak-CO and other echocardiographic parameters potentially useful to determine functional disability.
Results
In the overall population, peak-CO correlated significantly with peak-VO2 using all three methodologies (3-DE: R = 0.54, 2-DE: R = 0.55, Doppler: R= 0.56; all p< 0.001), demonstrating positive independent associations after adjustment for age, sex, and BMI. Volumetric peak-CO (2-DE/3-DE) showed consistent associations across HF phenotypes, whereas Doppler-derived CO was significantly associated with peak-VO2 only in HFrEF, and not in controls or HFpEF. Moreover, peak-CO emerged as the strongest independent predictor for impaired functional capacity compared with other echocardiographic parameters.
Conclusions
Peak left ventricular cardiac output is a strong and independent determinant of exercise capacity across the heart failure spectrum and in controls. Volumetric assessment - particularly 3-DE - provides consistent phenotype-independent associations and appears especially informative in HFpEF, where Doppler-derived CO does not demonstrate a significant relationship, supporting the incremental value of three-dimensional quantification during CPET imaging.Figure 1Figure 2