Study on the Correlation Between NAT2(N-acetyltransferase2) Gene Polymorphism and CrCl(Creatine Clreance) and the Efficacy and Safety of Levosimendan in Patients With Severe Heart Failure

Inclusion Criteria: * 18-80 years old * Patients who were clearly diagnosed with heart failure ( cardiac insufficiency ) and LVEF(Left Ventricular Ejection Fraction) \< 50 %, and were judged by the physician to need and agree to use levosimendan to maintain hemodynamic stability * Sign informed consent Exclusion Criteria: * chronic heart failure and New York Heart Association ( NYHA ) class I \~ II * Complicated with infective endocarditis, aortic dissection, severe liver dysfunction ( child-pugh C ), severe renal insufficiency ( CrCl \< 30 ml / min ), hypertrophic obstructive cardiomyopathy, ventricular assist device or surgical cardiac surgery within 30 days before the use of levosimendan * Patients with severe ventricular arrhythmia 1 within 24 hours before levosimendan and systolic blood pressure 100 times / min within 2 hours before levosimendan * During hospitalization, other positive inotropic drugs 2 were used when levosimendan was intravenously pumped or dripped, excluding the use of catecholamines for rescue * received positive inotropic drug 2 treatment in the last 30 days * Lack of serum creatinine, brain natriuretic peptide or brain natriuretic peptide precursor, serum total bilirubin, cardiac ultrasound baseline ( within 14 days before using levosimendan ) data * pregnant and lactating women