Heart & Circulation

Heart Failure: Symptoms, Causes, Diagnosis, and Treatment

A comprehensive patient guide to heart failure — what it is, why the heart does not stop, types (HFrEF and HFpEF), symptoms, causes, diagnosis, treatment, and when to seek help.

11 min read

Heart Failure: Symptoms, Causes, Diagnosis, and Treatment

Heart failure affects approximately 64 million people worldwide and is one of the most common reasons for hospital admission in adults over 65. Despite its name, it does not mean the heart has stopped — it means the heart is unable to pump blood effectively enough to meet the body’s demands, or can only do so at abnormally high pressures.

Heart failure is a serious, chronic condition that requires ongoing management. With the right medicines, lifestyle changes, and monitoring, most people with heart failure can maintain a good quality of life.

What Heart Failure Is — and What It Is Not

Heart failure is not a heart attack. It is not cardiac arrest. And it does not mean the heart is about to stop.

It means the heart’s pumping or filling function has been compromised — usually gradually over time — to a point where the body is not getting enough blood and oxygen to function well. The heart compensates by working harder and retaining fluid, which creates the characteristic symptoms of breathlessness, swelling, and fatigue.

Types of Heart Failure

Heart failure is classified by ejection fraction (EF) — the percentage of blood the heart pumps out with each beat from the main pumping chamber (left ventricle). A healthy ejection fraction is typically 55–70%.

HFrEF — Heart Failure with Reduced Ejection Fraction

  • Ejection fraction below 40%
  • The heart muscle is weakened and contracts poorly
  • Often caused by coronary artery disease, previous heart attack, or cardiomyopathy
  • Well-studied treatments with strong evidence for survival benefit

HFmrEF — Heart Failure with Mildly Reduced Ejection Fraction

  • Ejection fraction 40–49%
  • An intermediate category between reduced and preserved
  • Management is similar to HFrEF; evidence base is growing

HFpEF — Heart Failure with Preserved Ejection Fraction

  • Ejection fraction 50% or above
  • The heart contracts normally but the muscle is stiff and does not relax properly between beats
  • Common in older adults, women, those with high blood pressure, obesity, or diabetes
  • Often harder to diagnose; treatment focuses on underlying causes and symptom relief
  • SGLT2 inhibitors now have evidence for benefit in HFpEF

Severity: The NYHA Classification

The New York Heart Association (NYHA) classification grades heart failure by symptom severity:

ClassDescription
INo symptoms; ordinary activity does not cause breathlessness or fatigue
IIMild symptoms on ordinary activity; comfortable at rest
IIISymptoms on less-than-ordinary activity; comfortable only at rest
IVSymptoms at rest; any activity causes discomfort

Symptoms

Heart failure typically causes a combination of:

Breathlessness (dyspnoea)

  • On exertion initially — climbing stairs, walking briskly
  • Progresses to breathlessness at rest in advanced disease
  • Lying flat at night causes breathlessness (orthopnoea) — many people need multiple pillows
  • Waking suddenly breathless, often relieved by sitting upright (paroxysmal nocturnal dyspnoea or PND)

Fluid retention

  • Ankle, leg, and occasionally abdominal swelling (peripheral oedema)
  • Rapid unexplained weight gain (fluid accumulation)
  • Feeling bloated or full quickly after eating

Fatigue and weakness

  • Persistent tiredness disproportionate to activity
  • Reduced ability to exercise or complete daily tasks

Other symptoms

  • Persistent cough or wheeze (sometimes with pink-tinged mucus)
  • Dizziness or light-headedness, particularly when standing
  • Reduced urine output
  • Palpitations (commonly associated with atrial fibrillation)
  • Confusion or poor concentration (in advanced disease)

Causes

Heart failure results from conditions that damage or overwork the heart over time:

Most common causes:

  • Coronary artery disease and heart attack — the most common cause in men; blocked arteries damage heart muscle
  • High blood pressure (hypertension) — forces the heart to overwork, eventually causing it to stiffen or weaken
  • Atrial fibrillation — uncontrolled persistent AF weakens the heart over time

Other important causes:

  • Diabetes — independently damages heart muscle and blood vessels
  • Valve disease — leaking or narrowed valves place extra strain on the heart
  • Cardiomyopathy — disease of the heart muscle itself (including dilated, hypertrophic, and peripartum cardiomyopathy)
  • Chronic kidney disease — cardiorenal syndrome: heart and kidney disease worsen each other
  • Excessive alcohol use — alcoholic cardiomyopathy
  • Certain chemotherapy drugs — anthracyclines and other cardiotoxic agents
  • Obesity — increases cardiac workload and is linked to HFpEF
  • Obstructive sleep apnoea — repeated episodes of low oxygen strain the heart

Diagnosis

Heart failure is diagnosed using a combination of clinical assessment and investigations.

Blood Tests

  • BNP (B-type natriuretic peptide) or NT-proBNP — hormones released when the heart is under strain; a key diagnostic marker and indicator of severity
  • Full blood count, renal function, liver function, thyroid function — to identify contributing causes and complications
  • HbA1c and glucose — to check for diabetes

Echocardiogram (Heart Ultrasound)

The most important single test. An echocardiogram:

  • Measures ejection fraction (to classify HFrEF vs HFpEF)
  • Assesses heart muscle movement and wall thickness
  • Evaluates valve function
  • Detects pericardial fluid

ECG (Electrocardiogram)

  • Identifies rhythm abnormalities (particularly atrial fibrillation)
  • Detects evidence of previous heart attack
  • Identifies left ventricular hypertrophy from longstanding hypertension

Chest X-ray

  • Shows heart size (cardiomegaly)
  • Demonstrates pulmonary oedema (fluid in the lungs)
  • Identifies pleural effusions (fluid around the lungs)

Additional Tests (if indicated)

  • Cardiac MRI — detailed assessment of heart muscle structure and function
  • Coronary angiography — to identify blockages in coronary arteries
  • Exercise testing — to assess functional capacity
  • Holter monitor — for arrhythmia detection

Treatment

Treatment aims to relieve symptoms, reduce hospital admissions, slow disease progression, and improve survival.

Medications for HFrEF

Evidence-based medicines for HFrEF form what is often called the “fantastic four” — four classes of medicine each proven independently to reduce mortality:

1. ACE inhibitors / ARBs / ARNI (sacubitril/valsartan)

  • Relax blood vessels, reduce heart workload, and protect the heart from further damage
  • ACE inhibitors (e.g., ramipril, perindopril) or ARBs (e.g., candesartan) are first-line
  • ARNI (sacubitril/valsartan, brand name Entresto) offers superior survival benefit and is recommended for those who tolerate it

2. Beta blockers

  • Slow the heart rate, lower blood pressure, and reduce the heart’s workload
  • Examples: bisoprolol, carvedilol, metoprolol succinate
  • Must be started at low dose and titrated slowly

3. Mineralocorticoid receptor antagonists (MRAs)

  • Block aldosterone, reducing fluid retention and fibrosis
  • Examples: spironolactone, eplerenone
  • Require monitoring of kidney function and potassium

4. SGLT2 inhibitors

  • Originally developed for diabetes but now proven to reduce hospitalisations and death in heart failure, with and without diabetes
  • Examples: dapagliflozin (Forxiga), empagliflozin (Jardiance)
  • Also beneficial in HFpEF

Diuretics (for symptom relief)

  • Furosemide (frusemide), bumetanide
  • Remove excess fluid from the body, rapidly relieving breathlessness and swelling
  • Not proven to improve survival but essential for symptom control
  • Dose is often adjusted by the patient based on daily weight monitoring

Device Therapy

  • ICD (implantable cardioverter-defibrillator) — for those with severely reduced EF (typically <35%) at risk of sudden cardiac death
  • CRT (cardiac resynchronisation therapy) — for those with bundle branch block; helps the heart’s chambers pump in synchrony

Managing HFpEF

  • SGLT2 inhibitors (empagliflozin, dapagliflozin)
  • Diuretics for fluid relief
  • Aggressive management of underlying causes: blood pressure control, treating atrial fibrillation, weight loss, managing diabetes
  • No agent equivalent to the “fantastic four” for HFrEF has yet been shown to reduce mortality in HFpEF

Lifestyle and Self-Management

Fluid and Salt

  • Restrict dietary salt (sodium) — a low-salt diet reduces fluid retention
  • Fluid restriction (typically 1.5–2 litres per day) is sometimes advised in advanced disease; discuss this with your care team
  • Avoid excess alcohol, which worsens heart muscle function

Daily Weight Monitoring

Weighing yourself each morning (after urinating, before eating) is one of the most important self-management tools. A gain of 2 kg or more over 24–48 hours often indicates fluid retention and warrants contacting your GP or heart failure nurse. See also: Heart Failure Warning Signs

Exercise and Cardiac Rehabilitation

Exercise is safe and strongly recommended for most people with stable heart failure. Regular, moderate physical activity:

  • Improves exercise capacity and quality of life
  • Reduces hospital admissions
  • Reduces symptoms of depression and anxiety

Cardiac rehabilitation programmes designed for heart failure are available in most Australian states. Ask your cardiologist or GP for a referral.

Vaccinations

  • Annual influenza vaccine is recommended
  • Pneumococcal vaccine is recommended
  • COVID-19 vaccination as per current guidelines

Avoiding Triggers

  • NSAIDs (anti-inflammatory pain medicines such as ibuprofen and naproxen) can worsen heart failure by promoting fluid retention — avoid unless advised by your doctor
  • Some calcium channel blockers (verapamil, diltiazem) worsen HFrEF — check all medicines with your care team

Prognosis

Heart failure prognosis has improved substantially over the past 20 years due to modern medicines and device therapy. Important context:

  • HFrEF treated with all four evidence-based medicine classes has markedly improved outcomes compared to treatment even a decade ago
  • HFpEF prognosis is primarily driven by underlying conditions (hypertension, diabetes, obesity)
  • Prognosis varies widely by age, comorbidities, NYHA class, and response to treatment
  • Many people live with heart failure for years or decades, maintaining good quality of life
  • Hospitalisation for decompensation is an important risk marker — aggressive outpatient management aims to reduce admissions

Prognosis discussions should be had with your cardiologist or GP, who can give a personalised assessment based on your specific situation.

When to Seek Urgent Help

Call 000 (Australia) or your local emergency number immediately for:

  • Sudden severe shortness of breath at rest
  • Chest pain or pressure
  • Rapid weight gain of more than 2 kg in 24–48 hours
  • Severe or suddenly worsening ankle swelling
  • Blue lips, fingertips, or face (cyanosis)
  • Fainting or loss of consciousness
  • Confusion or sudden deterioration in mental state
  • Rapid, irregular, or pounding heartbeat with dizziness

Contact your GP or heart failure nurse promptly (same day) for:

  • Increasing breathlessness over days
  • Gradual weight gain of 1–2 kg over several days
  • Worsening ankle swelling
  • Reduced urine output
  • New or worsening cough

See the full guide: Heart Failure Warning Signs: When Symptoms Need Urgent Care

FAQ

Q: Does heart failure mean my heart will stop? No. Heart failure means the heart’s pumping function is impaired — not that it is about to stop. With appropriate treatment, most people with heart failure live for many years.

Q: What is ejection fraction? Ejection fraction (EF) is the percentage of blood pumped out of the left ventricle with each beat. A normal EF is around 55–70%. In HFrEF, EF is below 40%. It is measured by echocardiogram.

Q: Can heart failure be reversed? In some cases, yes. If caused by a reversible trigger (uncontrolled blood pressure, tachycardia from AF, alcohol, or certain medicines), the heart can recover significant function when the cause is treated. In most cases, the structural changes persist but can be stabilised.

Q: Are SGLT2 inhibitors only for diabetics? No. SGLT2 inhibitors such as dapagliflozin and empagliflozin are now approved for heart failure regardless of whether the person has diabetes. They reduce hospitalisations and improve outcomes.

Q: What is sacubitril/valsartan (Entresto)? Sacubitril/valsartan (brand name Entresto) is an ARNI — a combination of an ARB (valsartan) and a neprilysin inhibitor (sacubitril). It is more effective than ACE inhibitors alone at reducing hospitalisation and death in HFrEF, and is now preferred where tolerated.

Q: Can I exercise with heart failure? Yes, for most people with stable heart failure. Supervised exercise — particularly through cardiac rehabilitation — is recommended and improves quality of life and reduces hospital admissions. Always discuss your exercise plan with your care team first.

Further Reading

Educational only — not a substitute for professional medical advice. Always speak with your GP, cardiologist, or heart failure nurse about your specific situation.