I have hf with pef and no usual symptoms. I try to walk 4-5 times per week. I walk 1 1/2 miles in 30 minutes. I am experiencing some tiredness but just upped metoprolol and that seems to have increased fatigue. I am in Afib all the time and the Drs. are controlling the rate with meds. I have not heard of this clinical trial. Sure hope it works.