Udenafil Therapy to Improve Symptomatology, Exercise Tolerance and Hemodynamics in Patients With Chronic Systolic Heart Failure

"Capsule, appears identical with udenafil, will be provided by Dong-A pharmaceutical company.~Patients will receive 50 mg of placebo drug two times a day for 4 weeks, and then the dosage will be escalated to 100 mg two times a day for next 8 weeks"

Udenafil (Zydena), a newly developed PDE-5 inhibitor by Dong-A pharmaceutical company, will be administered to patients in this group, 50 mg two times a day for 4 weeks, and then the dosage will be escalated to 100 mg two times a day for next 8 weeks.