Abstract 1653: Total Heart Volume Independently Predicts Maximal Work Capacity in Normals and Athletes
Introduction: Maximal oxygen uptake (VO2 max) is used as a measurement of maximal work capacity. VO2 depends on cardiac parameters such as heart rate and stroke volume and also on peripheral parameters such as arterio-venous oxygen difference and hemoglobin concentration. Our hypothesis was that a larger healthy heart in itself, independent of body size parameters, can generate a larger cardiac output and therefore a higher VO2 max. The aim of this study was therefore to investigate if total heart volume (THV) independently can predict maximal work capacity. To our knowledge, no previous study has examined the relationship between total heart volume determined by cardiac MRI and VO2 max.
Methods: 36 athletes (6 female) and 27 controls (12 female) underwent cardiac MRI and maximal incremental exercise test on ergometer cycle with gas analysis. THV was calculated using planimetry derived from steady state free precession cine images. Multivariate regression analysis was performed for THV, body surface area (BSA) and height.
Results: Linear regression showed that VO2 correlated with BSA (r2=0.46, p<0.001), height (r2 = 0.36, p<0.001) and THV (r2 = 0.72, p<0.001). Multivariate linear regression analysis showed that THV was the strongest predictor of VO2 max (r2= 0.72, p<0.001). A combined model of THV and BSA gave a marginal increase in predictive value (r2 = 0.75, p<0.05).
Conclusion: Our results show that total heart volume predicts maximal work capacity independently of body surface area and height in normals and athletes.