Patients with heart failure are frequently treated with diuretics, including furosemide and torsemide, but it is not known if one is better than the other. The TRANSFORM-HF trial is studying if torsemide is superior than furosemide for reducing the endpoint of death or hospitalization, but is not designed to study why. This ancillary study seeks to measure proteins in the blood and urine to help explain the underlying mechanism for why patients who take one of these diuretics may have better outcomes than patients who take the other.

Patients who are enrolling in the TRANSFORM-HF study or being prescribed Torsemide or Furosemide at hospital discharge will provide blood and urine at the time of study enrollment (within 72 hours of hospital discharge) and at 90 days (+/- one week) after hospital discharge.

Inclusion Criteria:

• Participation in the TRANSFORM-HF trial or prescription of Torsemide or Furosemide
• Willing to provide blood and urine sample at enrollment and follow-up

Exclusion Criteria:

• Inability or unwillingness to comply with the study requirements

This study will enroll a subset of patients who are enrolling in the TRANSFORM-HF study during a hospitalization for acute HF, or who are prescribed Torsemide or Furosemide at hospital discharge, and who are willing to provide biospecimens for analysis.