Trial design
HEART
The trial was a prospective, investigator initiated, double-blind, randomised, placebo controlled, parallel-group clinical trial, performed at the Clinical Research Centre of the University Hospital Erlangen, Germany. We recruited patients with HFrEF or HFmrEF, according the 2016 ESC guidelines definition, from the University outpatient clinic as well as through newspaper advertisements. All patients had to be in a stable condition with New York Heart Association class (NYHA) II–III.Each patient entered, after being screened for eligibility, a 2-weeks run-in phase where, if necessary, change of medication to meet the patient’s clinical condition or additional diagnostics (e.g. echocardiogram) took place. After the 2-weeks run-in phase, being naive to or off any SGLT2 inhibitor for at least 10 weeks, patients underwent the first Trial design: summary of study visits and tests performed in each visitAfter 