Hepatitis C Virus(HCV) Heart and Lung Study

Inclusion Criteria: * Chronic HCV Infection of Genotype 1, 4, 5, or 6 * HCV RNA \> 103 IU/mL at screening * 18 years of age or older * Diagnosis of chronic HCV infection, defined as positive HCV antibody or HCV RNA more than 6 months prior to screening OR an assessment of fibrosis F2 or greater prior to screening. Subjects in the advanced heart failure cohort must meet all HCV criteria, and all of the following criteria: * New York Heart Association (NYHA) Class III or IV functional classification * NYHA Class III: Subjects with cardiac disease resulting in marked limitation of physical activity. They are comfortable at rest. Less than ordinary physical activity causes fatigue, palpitation, dyspnea, or anginal pain. * NYHA Class IV: Patient with cardiac disease resulting in inability to carry on any physical activity without discomfort. Symptoms of cardiac insufficiency or of the anginal syndrome may be present even at rest. If any physical activity is undertaken, discomfort is increased. * ejection fraction ≤ 30% * hospitalized for heart failure in last 12 months Subjects in the advanced lung disease cohort must have been diagnosed with chronic obstructive pulmonary disease (COPD) or interstitial lung disease (ILD) must meet all HCV criteria, and meet the following criteria for COPD or ILD: * ILD criteria: diagnosis of interstitial lung disease with chronic supplemental oxygen requirement at rest and/or with exertion. * COPD criteria (one of the following): * Forced expiratory volume (FEV1)\< 30% predicted * OR any FEV1 with chronic supplemental oxygen requirement at rest and/or with exertion * OR any FEV1 with chronic hypercapnia (baseline partial pressure of arterial carbon dioxide \[PaCO2\] \> 45) Exclusion Criteria: * Chronic HCV Infection with Genotype 2 or 3 * Treatment with any of the following agents * Amiodarone. Subjects previously treated with amiodarone must have stopped the amiodarone at least 60 days prior to day 1 of SOF/LDV FDC * Carbamazepine, phenytoin, phenobarbital, oxcarbazepine * Rifabutin, rifampin or rifapentine * HIV regimens containing tenofovir or tipranavir/ritonavir * St. John's wort * Rosuvastatin * Have any serious or active medical or psychiatric illness which, in the opinion of the investigator, would interfere with subject treatment, assessment, or compliance * History of hepatic encephalopathy or variceal hemorrhage * Hepatitis B surface antigen positive * Abnormal hematological and biochemical parameters, including: * Hemoglobin (Hb) \< 8 g/dL * Platelets ≤ 50,000/mm3 * alanine aminotransferase (ALT), aspartase aminotransferase (AST), or alkaline phosphatase ≥ 10 times upper limit of normal(ULN) * Total bilirubin \> 3 mg/dl * Severe renal impairment creatinine clearance (CrCl), i.e. \< 30 mL/min. * History of major organ transplantation with an existing functional graft. * History of clinically-significant drug allergy to nucleoside/nucleotide analogs. * Pregnant women or women planning to become pregnant * Women who are breastfeeding * Active or recent history (≤ 1 year) of drug or alcohol abuse