The goal of TAILOR-HF is to integrate clinical data, laboratory parameters, treatment patterns, and circulating biomarkers to identify factors that predict individual response to pharmacological treatment in patients with heart failure.

TAILOR-HF is an observational study with protocol-mandated assessments scheduled at baseline and at 1, 3, and 6 months after enrolment. Additional follow-up data will be collected through telephone visits every 6 months until the last participant has completed the protocol-mandated 6-month visit.

Inclusion Criteria:

1. Provide written and dated informed consent for participation prior to trial admission,
2. Age ≥18 years, female or male
3. A clinical diagnosis of new onset or worsening of heart failure with a left-ventricular ejection fraction of <50%
4. On treatment with oral or i.v. furosemide ≥40 mg/day or equivalent (bumetanide 1mg, torasemide 10mg)
5. Receiving <50% of the target doses of at least one of the guidelines recommended pharmacological therapies (clear intolerance not considered)
6. Anticipated or planned uptitration

Exclusion Criteria:

1. Scheduled or on renal replacement therapy,
2. Clearly documented intolerance to two or more of the following groups of drugs: BB, ARNI, SGLT2i or MRAs.
3. Diagnosis of peripartum cardiomyopathy, chemotherapy induced cardiomyopathy, current viral myocarditis, right heart failure in absence of left-sided structural disease, pericardial constriction, genetic hypertrophic cardiomyopathy, or infiltrative cardiomyopathy including amyloidosis.
4. The presence of a mechanical assist device,
5. Scheduled for mechanical assist device or heart transplant,
6. Current angina pectoris ≥class III,
7. Requiring valvular surgery or revascularization in the upcoming 3 months or Coronary Artery Bypass Grafting (CABG) within the past 3 months,
8. Anticipated need for surgery or any other cardiovascular intervention, except implantable cardioverter defibrillator and/or cardiac resynchronization therapy, within 4 weeks,
9. Other non-cardiac conditions with limited life expectancy (≤ duration of the trial/ 1 year),
10. Participation in another clinical trial apart from non-interventional studies.
11. Patients with an unscheduled hospital visit or admission for reasons that are not primarily related to worsening of heart failure. Therefore, patients with concomitant pulmonary disease, even if severe, valvular disease, acute coronary syndrome or stroke, may be included when the primary diagnosis for admission to hospital or outpatient clinic visit has been heart failure, rather than the concomitant condition.
12. Women who are pregnant, breastfeeding or those considering becoming pregnant
13. Subjects unable to provide informed consent.

Patients with either de novo HF or (acute) decompensated HF who are not yet on optimal doses of guideline-recommended therapies and in whom up-titration is anticipated.

Patients will be enrolled either at the outpatient clinic of participating sites or prior to dis-charge of patients who are hospitalized for worsening HF