Immediate Release Versus Slow Release Carvedilol in Heart Failure

Inclusion criteria: 1. At least or more than 20-years-old male and female 2. Confirmed left ventricular ejection fraction ≤40% by echocardiography within pre-analytical 6 months 3. NT-proBNP level ≥ 125 pg/ml or BNP level ≥ 35 pg/ml within pre-analytical 3 months 4. Clinically stable patient without evidence of congestion or extracellular fluid retention; those could be candidate of β-blockers 5. Patients providing written informed consent Exclusion Criteria: 1. Systolic blood pressure at sitting position \< 90mmHg or resting heart rate \< 50 /min at screening 2. Patient has a contraindication to β-blockers 3. Patient who are expected to take another β-blocker after randomization 4. Cardiovascular diseases * Ischemic heart disease (unstable angina, myocardial infarction) within 1 month * Hypertrophic cardiomyopathy * Cor pulmonale * Hemodynamically significant stenosis of aorta, aortic valve, or mitral valve * any acute myocardial infarction with complication 5. Severe cerebrovascular accident (for example, ischemic stroke or cerebral hemorrhage) pre-analytical within 6 months 6. Glottis edema, allergic rhinitis, respiratory diseases with bronchospasm such as asthma and chronic obstructive lung disease 7. Peripheral vascular disease (for example, Raynaud syndrome, intermittent claudication) 8. Patients who need vasopressor due to prominent volume retention/overload 9. Moderate to Severe retinopathy (for example, retinal hemorrhage, visual disturbance, retinal microaneurysm within 6 months) 10. Impaired renal function (Serum creatinine ≥ 2.5 mg/dL) or hepatic function (AST or ALT ≥ 3 x ULM) 11. Patients in clinical status that can significantly influence on absorption, distribution, metabolism, and secretion of drugs for clinical trial * history of major gastrointestinal surgery, such as gastrectomy or gastric bypass surgery * inflammatory bowel disease within 12 months * current gastric ulcer, pancreatic function abnormality including pancreatitis, gastrointestinal/rectal bleeding which demand treatment * current urologic stenosis or obstruction which demand treatment 12. Confirmed or suspected drug/alcohol abuse within 6 months 13. Pregnant or lactating women, suspected pregnant women or lactating women 14. Chronic inflammatory diseases which demand anti-inflammatory treatment 15. Hypersensitivity to carvedilol 16. Malignant disease including lymphoma and leukemia within 5 years 17. Patients who were prescribed other medication for any clinical trials pre-analytical within 28 days 18. Patients who are predicted to have prolonged hospital days due to other medical problems other than chronic heart failure (for example, femur neck fracture) 19. Patients who are considered as inappropriate to participate in the clinical trial by testers