DYNAMIC CHANGES IN LEFT VENTRICULAR FUNCTION ON EXERCISE IN HEART FAILURE WITH PRESERVED EJECTION FRACTION: THE ROLE OF MYOCARDIAL ENERGY DEFICIENCY by Phan, T, Abozguia, K, Shivu, T, Gnanadevan, M, Ahmed, I, Williams, L, Dwivedi, G, Patel, K, Steendijk, P, Ashrafian, H, Henning, A, Frenneaux, M