ACE and diastolic heart failure: The Japanese Diastolic Heart Failure (J-DHF) study[25] suggested the usefulness of β-blockers, but in randomized large-scale clinical trials, such as the Perindopril in Elderly People with Chronic Heart Failure (PEP-CHF) trial,[26] which used angiotensin converting enzyme inhibitors, in addition to the Candesartan in Heart Failure-Assessment of Reduction in Mortality and Morbidity-Preserved (CHARM-Preserved) trial[27] and I-PRESERVE trial,[28] both of which used angiotensin receptor antagonists (ARBs), did not show the usefulness of drug treatments.