The simplest terminology used to describe the severity of heart failure is the New York Heart Association (NYHA) functional classification. It is based on the patient's symptoms and helps guide treatment. 

In addition, the NYHA class helps determine reimbursement for certain drugs. For example: 

• An NYHA class II or higher is necessary for reimbursement of e.g. SGLT2 inhibitors, ARNI,...
• In cardiac ATTR amyloidosis, tafamidis is no longer reimbursed at NYHA class III and IV.