Abstract Body (Do not enter title and authors here): Introduction: Low fitness and exaggerated left ventricular (LV) filling pressures are defining features of Heart Failure with Preserved Ejection (HFpEF). The augmented LV filling pressure in HFpEF may be a consequence of early diastolic dysfunction. Whether exercise training influences early diastolic function in patients with HFpEF is unknown. The aim of this study was to define early diastolic function in patients with HFpEF before and after aerobic exercise training.

Methods: Patients with HFpEF completed 4 months of aerobic exercise training randomized between systemic aerobic training (cycling, n = 24, 69±8 years, 69% female) or targeted small muscle mass training (single knee extension [SKE], n = 20, 71±6, 75% female). Before and after training, patients underwent a cardiopulmonary exercise test with right heart catheterization, radial arterial line, and concurrent echocardiography. Early diastole was characterized by time constant of LV relaxation (Tau), isovolumetric relaxation time (IVRT), early diastolic recoil velocity (e’), and E/e’ ratio. Markers were measured at rest and during 20W steady-state exercise. Differences between exercise modalities before and after training were compared.

Results: Patients in the cycling group significantly increased by their peak VO2 (1.7±2.1 ml/kg/min) with training compared to the SKE group (0.1±1.1 ml/kg/min, Group x time interaction = 0.004). Results are shown at rest in Table 1 and during 20W exercise in Table 2. There were no significant differences after training in pulmonary capillary wedge pressure (PCWP), Tau, IVRT, E’ or E/e’ either at rest or during exercise. There was no significant difference between exercise modalities.

Conclusions: Systemic aerobic exercise training improved fitness in patients with HFpEF but neither modality of exercise training improved LV filling pressures or any aspect of early diastolic function at rest or during sub-maximal exercise. Alternative therapeutic strategies are needed to improve left ventricular relaxation in patients with HFpEF.