4 Heart Failure

Heart failure and its clinical patterns

Heart failure (HF) is a clinical syndrome in which a structural or functional problem of the heart causes symptoms or signs, often breathlessness, fatigue, or fluid retention. It may result from coronary artery disease, hypertension, valve disease, cardiomyopathy, or rhythm disorders. HF is a long-term condition that can worsen suddenly, so timely recognition and treatment of decompensation are essential.

Clinical patterns

HF may be described as left-sided or right-sided, and as acute when it is new or rapidly worsening, or chronic. Left-sided congestion commonly causes breathlessness and pulmonary edema; right-sided congestion often causes raised neck veins, leg swelling, or abdominal fluid. These patterns can overlap.

The New York Heart Association functional classes $\mathrm{I}$–$\mathrm{IV}$ describe how much ordinary activity is limited by symptoms. ACC/AHA stages $\mathrm{A}$–$\mathrm{D}$ describe disease progression from risk through advanced HF.

Classification by ejection fraction

A common classification uses LVEF, the percentage of blood in the left ventricle ejected with each contraction. Echocardiography assesses LVEF as well as chamber size, valves, and other structural or functional abnormalities.

• HFrEF: LVEF $\leq 40\%$, with impaired systolic pumping. Evidence-based disease-modifying therapies are especially well established for this group.

• HFmrEF: LVEF from $41\%$ to $49\%$. Diagnosis also relies on evidence of raised filling pressures or other objective evidence of HF.

• HFpEF: LVEF $\geq 50\%$. The ejection fraction is preserved, but filling pressures are elevated or the heart has other structural or functional abnormalities.

• HFimpEF: Previous LVEF $\leq 40\%$, now $>40\%$. Ejection fraction has improved with time or treatment, but this does not necessarily mean the underlying HF has resolved.

Assessment and diagnosis

Assessment combines symptoms, examination, and testing; no single symptom or examination finding proves or excludes HF.

Ask about breathlessness on exertion or when lying flat, waking at night short of breath, reduced exercise tolerance, fatigue, swelling, rapid weight gain, abdominal fullness, and changes in urination or thinking. Examine vital signs, oxygenation, neck veins, lung sounds, peripheral edema, skin temperature, and perfusion.

Diagnostic tests and causes

• Echocardiography assesses LVEF, chamber size, valves, and other structural or functional abnormalities.

• BNP or NT-proBNP can support diagnosis and help assess severity; interpret results in clinical context.

• ECG, chest imaging, and blood tests help identify rhythm problems, congestion, possible ischemia, and effects on kidney function, electrolytes, liver, and blood count.

Look for the cause of HF and potentially reversible contributors, such as ischemia, valve disease, uncontrolled blood pressure, or arrhythmia.

Acute worsening and urgent care

Acute decompensated HF is a new or worsening episode requiring urgent assessment, often in hospital. It may develop gradually or present suddenly with severe pulmonary edema. Common triggers include infection, ischemia or myocardial infarction, uncontrolled blood pressure, arrhythmia, missed medication, excess sodium or fluid, kidney dysfunction, and drugs that worsen fluid retention or cardiac function.

Severe breathlessness at rest, low oxygen, chest pain, fainting, confusion, blue or clammy skin, very low blood pressure, or signs of shock require emergency care. Assess airway, breathing, circulation, oxygenation, blood pressure, mental status, rhythm, and evidence of congestion or poor perfusion. Investigate the trigger while stabilizing the patient; do not assume every episode of breathlessness is HF.

Stabilization and treatment

Treatment is individualized to oxygenation, blood pressure, kidney function, and degree of congestion. Clinicians commonly use intravenous loop diuretics for fluid overload and monitor symptoms, urine output, weight, kidney function, and electrolytes. Oxygen or ventilatory support is used when needed for hypoxemia or respiratory distress.

Vasodilators may be considered in selected patients with adequate blood pressure. Inotropes are generally reserved for severe low-output states or shock under specialist care. Treat the precipitating cause, such as infection, ischemia, or a dangerous arrhythmia.

Before discharge, confirm clinical improvement and create a plan for medication optimization, monitoring, follow-up, and what to do if symptoms recur. For eligible patients with HFrEF, starting or resuming disease-modifying treatment during hospitalization may be appropriate once the patient is clinically stable.

Long-term treatment

Management aims to improve symptoms and daily function, reduce hospitalization and premature death, and address the cause of HF. Treatment depends on HF type, blood pressure, kidney function, potassium, other conditions, and the person’s goals.

Disease-modifying treatment for HFrEF

For eligible patients with HFrEF, foundational guideline-directed medical therapy (GDMT) consists of four medication groups:

1. An ARNI (angiotensin receptor–neprilysin inhibitor), or an ACE inhibitor or ARB when an ARNI is unsuitable.

2. An evidence-based beta blocker.

3. A mineralocorticoid receptor antagonist (MRA).

4. An SGLT2 inhibitor, whether or not the patient has diabetes.

These therapies are introduced and adjusted with clinical monitoring. Kidney function, potassium, blood pressure, heart rate, and side effects influence treatment. When tolerated, clinicians generally aim to introduce the core therapies early and titrate them toward effective doses rather than maximizing one medicine before considering the others. Do not abruptly stop prescribed HF medicines without advice from the treating team.

Treatment across HF types

For HFmrEF and HFpEF, SGLT2 inhibitors can reduce HF events in appropriate patients. Diuretics relieve fluid congestion across ejection-fraction types, but are primarily for symptom and volume control rather than a substitute for disease-modifying therapy. Treat associated conditions such as hypertension, atrial fibrillation, coronary disease, diabetes, obesity, and sleep-disordered breathing as appropriate.

Self-care and follow-up

Self-care and follow-up support symptom control and allow treatment to be adjusted over time.

• Take medicines as prescribed and keep follow-up appointments; treatment often needs gradual adjustment.

• Track symptoms and, when advised, daily weight. Follow the care team’s action plan for reporting rapid weight increase, worsening swelling, increasing breathlessness, or reduced ability to exercise.

• Follow individualized advice about sodium, fluids, and activity; overly restrictive fluid limits are not appropriate for everyone.

• Avoid tobacco and excess alcohol. Ask a clinician or pharmacist before using over-the-counter medicines, as some, including nonsteroidal anti-inflammatory drugs, can worsen HF.

• Exercise or cardiac rehabilitation may be appropriate once the condition is stable. Include vaccination, mental-health support, and discussion of care preferences as part of comprehensive management.

Persistent symptoms despite treatment, repeated hospitalizations, or progressive kidney dysfunction warrant reassessment and consideration of referral to an HF specialist. Advanced therapies or supportive and palliative care may be appropriate for some patients.