A multicenter, randomized, double-blind, controlled study to evaluate the efficacy and safety of dantrolene on ventricular arrhythmia as well as mortality and morbidity in patients with chronic heart failure and reduced ejection fraction

INTERVENTION: oral administration of dantrolene or placebo administration period is for 2 years,3 times oral administration a day CONDITION: Patients with chronic heart failure who are at least 20 years, New Tork Heart Association (NYHA) class II and III, and LVEF<40% during treatment according to JCS and/or ACC/AHA and/or ESC heart failure guidelines. PRIMARY OUTCOME: a composite of death (cardiovascular and non‐cardiovasclar death), lethal arrhythmia (ventricular tachycardia(VT) storm, sustained VT, ventricular fibrillation)or a first hospitalization for exacerbation of heart failure 2 years after starting administration of dantrolene or placebo INCLUSION CRITERIA: 1)20 years and older 2)eligible for male and female 3)eligible for in‐patients and out‐patients 4) patients who fulfill all the following criteria. a) patients who receive treatment according JCS, ESC, AHA/ACC heart failure guidelines b)NYHA II and III c)LVEF is less than 40% d)BNP levels #ordinary, BNP level of at least 150pg/ml #if they had been hospitalized for heart failure within the previous 12 months, BNP level of at least 100pg/ml #if they had had VT or VF within the previous 12 months.