Salivary Extracellular Vesicle Associated lncRNAs in Heart Failure (SEAL-HF)

This study is looking for molecular markers (specifically certain types of genetic material) in saliva that might help doctors diagnose and monitor heart failure — potentially offering a simpler alternative to blood tests or invasive procedures. **You may be eligible if...** - You are 18 or older - You have been diagnosed with chronic heart failure (any type, with symptoms ranging from mild to severe) OR you have acute (sudden severe) heart failure currently being treated, OR you are having a heart procedure in the EP (electrophysiology) lab and can serve as a comparison participant **You may NOT be eligible if...** - You are pregnant or breastfeeding - You have cardiac amyloidosis (a specific type of heart disease) - You have an active cancer Talk to your doctor to see if this trial is right for you.