Heart failure is one of the most misunderstood cardiac conditions. Many patients hear the term and assume it means the heart has stopped working entirely. In reality, heart failure means the heart muscle has become too weak or too stiff to pump blood as efficiently as the body needs.
It is a chronic, progressive condition — but with early diagnosis, the right medications and lifestyle changes, many patients live active and fulfilling lives for years. This article explains the types, causes, stages, symptoms and current treatment options for heart failure in a way that patients and families can understand.
What Is Heart Failure?
Heart failure does not mean the heart has "failed" or stopped beating. It means the heart is unable to pump blood strongly enough to meet the body's demands for oxygen and nutrients. Over time, blood can back up in the lungs and other parts of the body, causing the characteristic symptoms of breathlessness, swelling and fatigue.
The heart tries to compensate by enlarging, developing thicker walls or pumping faster. The body also diverts blood away from less critical organs. These compensatory mechanisms work for a while, but eventually they contribute to further weakening of the heart muscle.
Key point: Heart failure is not a heart attack. A heart attack is a sudden blockage of blood flow to the heart muscle. Heart failure is a long-term condition where the heart gradually loses pumping ability. However, a heart attack can cause heart failure by damaging part of the heart muscle. See our guide on heart attack warning signs for more on that distinction.
Types of Heart Failure
Heart failure is classified in several ways. The most important distinction for treatment decisions is based on the ejection fraction (EF) — the percentage of blood the left ventricle pumps out with each beat. A normal EF is 55–70%. This is measured using a 2D echocardiogram (Echo).
| Type | Ejection Fraction | What It Means |
|---|---|---|
| HFrEF (Heart Failure with Reduced EF) | Less than 40% | The heart muscle is weakened and cannot contract strongly enough. This is the most common type and has the most well-studied treatments. |
| HFmrEF (Mildly Reduced EF) | 41–49% | A borderline category. The heart is mildly weakened. Treatment approach is similar to HFrEF in many cases. |
| HFpEF (Heart Failure with Preserved EF) | 50% or higher | The heart contracts normally but is stiff and does not relax properly, so it cannot fill with enough blood. Common in older adults, women, and those with hypertension, diabetes or obesity. |
Left-Sided vs Right-Sided Heart Failure
- Left-sided heart failure: The left ventricle cannot pump blood forward efficiently. Blood backs up into the lungs, causing breathlessness and cough. This is the most common form.
- Right-sided heart failure: The right ventricle cannot pump blood to the lungs effectively. Blood backs up in the veins, causing swelling in the legs, ankles and abdomen. Often develops as a consequence of left-sided failure.
- Biventricular heart failure: Both sides are affected. This usually indicates advanced disease.
Causes of Heart Failure
Heart failure is not a disease in itself — it is the end result of damage to the heart from various conditions. The most common causes include:
- Coronary artery disease (CAD): Narrowed or blocked arteries reduce blood supply to the heart muscle, weakening it over time. This is the leading cause of heart failure.
- Previous heart attack: A heart attack destroys a portion of the heart muscle. The dead muscle is replaced by scar tissue that cannot contract, reducing the heart's pumping ability permanently.
- Uncontrolled hypertension: High blood pressure forces the heart to work harder. Over years, the heart muscle thickens and eventually stiffens or weakens. This is a major cause of HFpEF. Read more about high blood pressure management.
- Valve disease: Damaged or diseased heart valves force the heart to work harder. Aortic stenosis and mitral regurgitation are the most common culprits.
- Cardiomyopathy: Disease of the heart muscle itself — dilated cardiomyopathy (heart stretches and thins), hypertrophic cardiomyopathy (heart thickens abnormally) or restrictive cardiomyopathy (heart becomes stiff).
- Diabetes: Chronic high blood sugar damages small blood vessels and the heart muscle directly, increasing heart failure risk even without blockages.
- Alcohol and substance abuse: Heavy, prolonged alcohol use can cause alcoholic cardiomyopathy, directly weakening the heart muscle.
- Other causes: Congenital heart defects, viral infections (myocarditis), thyroid disorders, severe anaemia, arrhythmias and chemotherapy-related damage.
In some patients, more than one factor contributes. Identifying and treating the underlying cause is a critical part of managing heart failure.
Symptoms of Heart Failure: Early vs Advanced
Heart failure symptoms develop gradually. Many patients dismiss early signs as "just getting older." Recognising these symptoms early can lead to earlier treatment and better outcomes.
| Symptom | Early Stage | Advanced Stage |
|---|---|---|
| Breathlessness | On exertion (climbing stairs, walking uphill) | At rest, while lying flat (orthopnoea), waking up gasping at night (PND) |
| Swelling (oedema) | Mild ankle swelling by evening, shoes feeling tight | Persistent swelling in legs, abdomen (ascites); rapid weight gain (1–2 kg overnight) |
| Fatigue | Tiring easily during routine activities | Exhaustion even at rest; unable to complete daily tasks |
| Cough | Occasional dry cough, worse when lying down | Persistent cough with white or pink-tinged phlegm |
| Appetite | Reduced appetite, feeling full quickly | Nausea, bloating, unintentional weight loss (cardiac cachexia) |
| Heart rate | Occasional palpitations or racing heartbeat | Persistent rapid or irregular heartbeat |
| Mental clarity | Mild difficulty concentrating | Confusion, memory problems, disorientation |
When to seek emergency help: If you experience sudden severe breathlessness, chest pain, fainting, or coughing up pink frothy sputum, go to the nearest emergency department immediately. These may indicate acute decompensated heart failure or a cardiac emergency.
NYHA Functional Classification: Stages of Heart Failure
The New York Heart Association (NYHA) classification is the most widely used system to describe how much heart failure limits a patient's daily activities. It helps doctors gauge severity, guide treatment and track progress.
| NYHA Class | Severity | What the Patient Experiences |
|---|---|---|
| Class I | No limitation | Ordinary physical activity does not cause symptoms. The patient may not even know they have heart failure. Diagnosed incidentally on Echo. |
| Class II | Mild limitation | Comfortable at rest. Moderate activities like climbing two flights of stairs or carrying groceries cause breathlessness or fatigue. |
| Class III | Moderate limitation | Comfortable only at rest. Even light activities such as getting dressed, walking across a room or bathing cause symptoms. |
| Class IV | Severe limitation | Symptoms present even at rest. Unable to carry out any physical activity without discomfort. May be bed-bound or chair-bound. |
NYHA class can change over time — with effective treatment, a patient in Class III can improve to Class II or even Class I. The classification also helps determine eligibility for advanced therapies such as device implantation.
How Is Heart Failure Diagnosed?
Diagnosis involves a combination of clinical assessment, blood tests and imaging. The key investigations include:
- 2D Echocardiogram (Echo): The single most important test. It measures the ejection fraction, assesses heart chamber sizes, wall thickness, valve function and filling pressures. This is how HFrEF and HFpEF are distinguished. Learn more about the 2D Echo test, cost and what to expect.
- BNP / NT-proBNP blood test: Brain natriuretic peptide is released when the heart is under strain. Elevated levels strongly suggest heart failure. It is also used to monitor treatment response — falling levels indicate improvement.
- ECG (Electrocardiogram): Identifies abnormal heart rhythms, signs of previous heart attack and conduction abnormalities. Learn more in our ECG test guide.
- Chest X-ray: Shows heart size (an enlarged heart silhouette) and fluid in the lungs (pulmonary congestion).
- Cardiac MRI: Provides detailed images of heart structure and function. Particularly useful for identifying the cause of cardiomyopathy, assessing scar tissue and measuring EF precisely.
- Coronary angiography: If coronary artery disease is suspected as the cause, an angiogram helps visualise blockages and determine whether revascularisation (angioplasty or bypass surgery) can help. See our comparison of CT angiography vs invasive angiography.
Additional tests such as a treadmill stress test (TMT), thyroid function tests, iron studies and renal function tests may be ordered depending on the clinical picture.
Treatment of Heart Failure
Heart failure treatment has improved dramatically over the past two decades. Modern therapy combines medications, device-based treatments, lifestyle changes, and in select cases, surgery. The goal is to relieve symptoms, slow disease progression, reduce hospitalisations and prolong life.
1. Medications: The Four Pillars
For HFrEF, current guidelines recommend four classes of drugs that have been proven to improve survival. These are often called the "four pillars" of heart failure therapy. The aim is to start all four as early as possible and titrate to target doses:
| Drug Class | Examples | How It Helps |
|---|---|---|
| ACE Inhibitors / ARBs / ARNI | Enalapril, Ramipril, Losartan, Sacubitril-Valsartan (Entresto) | Reduces strain on the heart by lowering blood pressure and preventing harmful remodelling. ARNI (Sacubitril-Valsartan) is preferred over ACE inhibitors when tolerated. |
| Beta-Blockers | Carvedilol, Bisoprolol, Metoprolol Succinate | Slows the heart rate, reduces the heart's workload and allows it to pump more efficiently. Proven to improve survival. |
| Mineralocorticoid Receptor Antagonists (MRA) | Spironolactone, Eplerenone | Blocks the harmful effects of aldosterone. Reduces fluid retention and prevents further heart muscle damage. |
| SGLT2 Inhibitors | Dapagliflozin (Forxiga), Empagliflozin (Jardiance) | Originally developed for diabetes, now proven to reduce heart failure hospitalisations and death even in non-diabetic patients. A major advance in treatment. |
In addition to the four pillars, other medications are used as needed:
- Diuretics (Furosemide, Torsemide): Remove excess fluid from the body to relieve breathlessness and swelling. Essential for symptom control but not shown to improve long-term survival.
- Digoxin: May be added if symptoms persist despite optimal therapy, or to control heart rate in atrial fibrillation.
- Hydralazine + Nitrate: An alternative for patients who cannot tolerate ACE inhibitors or ARBs.
- Ivabradine: Reduces heart rate in patients already on maximum beta-blocker doses.
Important: Never stop or adjust heart failure medications on your own. Sudden withdrawal of beta-blockers or ACE inhibitors can cause a dangerous rebound. All dose changes must be supervised by your cardiologist.
2. Device Therapy
When medications alone are not enough, implantable devices can significantly improve outcomes:
- CRT (Cardiac Resynchronisation Therapy): A specialised pacemaker that coordinates the contraction of the left and right ventricles. Recommended for patients with EF ≤35%, NYHA Class II–IV symptoms and a wide QRS complex on ECG (typically ≥150 ms). CRT can improve EF by 5–15 percentage points and significantly reduce symptoms. See our guide on pacemaker implantation.
- ICD (Implantable Cardioverter-Defibrillator): Monitors heart rhythm and delivers a shock if a life-threatening arrhythmia (ventricular tachycardia or fibrillation) occurs. Recommended for patients with EF ≤35% who are at risk of sudden cardiac death. Often combined with CRT as a CRT-D device.
The decision to implant a device is made after the patient has been on optimal medical therapy for at least three months, as EF may improve with medications alone.
3. Lifestyle Modifications
Lifestyle changes are not optional — they are a core part of treatment:
- Salt restriction: Limit sodium intake to less than 2 grams per day (approximately one teaspoon of table salt). Excess salt causes fluid retention, worsening breathlessness and swelling.
- Fluid management: In moderate to severe heart failure, fluid intake may need to be restricted to 1.5–2 litres per day, as advised by your doctor.
- Daily weight monitoring: Weigh yourself every morning, after using the bathroom, before eating. A sudden gain of more than 1.5–2 kg in 2–3 days usually means fluid build-up and should prompt a call to your doctor.
- Exercise rehabilitation: Supervised cardiac rehabilitation with graded exercise is safe and beneficial. Regular moderate activity (walking, light cycling) improves exercise tolerance, quality of life and reduces hospitalisations. Your cardiologist will advise on what level of activity is appropriate for your stage.
- Smoking and alcohol cessation: Smoking damages blood vessels and accelerates heart failure. Alcohol weakens the heart muscle directly. Both must be stopped completely.
- Vaccination: Annual influenza and pneumococcal vaccination are recommended, as respiratory infections can trigger acute decompensation in heart failure patients.
4. Surgical Options
In specific situations, surgery may be needed to treat the underlying cause or manage end-stage disease:
- Coronary artery bypass grafting (CABG): If coronary artery disease is the cause and multiple arteries are blocked, bypass surgery can restore blood supply to the heart muscle. See our comparison of CABG vs angioplasty.
- Valve repair or replacement: If a damaged valve is causing or worsening heart failure, surgical repair or replacement (including TAVI for aortic stenosis in high-risk patients) can improve function.
- Left ventricular assist device (LVAD): A mechanical pump implanted in the chest to help the weakened heart pump blood. Used as a bridge to heart transplant or as long-term therapy in patients who are not transplant candidates.
- Heart transplant: The definitive treatment for end-stage heart failure that does not respond to all other therapies. Reserved for patients under approximately 65 years with no other life-limiting conditions. Availability is limited by donor organ supply.
Living with Heart Failure: Daily Management
Heart failure is a condition that requires active daily self-management. Patients who monitor their symptoms and follow their care plan closely have fewer hospitalisations and better quality of life.
Daily Checklist
- Weigh yourself every morning (same time, same scale)
- Take all medications as prescribed
- Keep salt intake below 2 grams
- Monitor fluid intake if advised
- Walk or do light exercise as tolerated
- Check for new or worsening ankle swelling
- Note any change in breathlessness
Call Your Doctor If
- Weight gain of more than 1.5–2 kg in 2–3 days
- New or worsening breathlessness
- Increased swelling in legs or abdomen
- Need to prop up with extra pillows to sleep
- Persistent cough or wheezing
- Dizziness or fainting
- Rapid or irregular heartbeat at rest
Family members and caregivers play an important role. Understanding the condition, helping with medication schedules, preparing low-salt meals and recognising warning signs early can prevent many emergency hospital visits.
Frequently Asked Questions
Can heart failure be cured?
Heart failure is usually a chronic condition that cannot be fully cured. However, in some cases where the cause is reversible — such as alcohol-related cardiomyopathy (if alcohol is stopped early), thyroid-related heart failure, or tachycardia-induced cardiomyopathy — the heart function can return to normal. In most cases, the goal of treatment is to manage symptoms, slow progression and improve quality of life. With modern four-pillar drug therapy, many patients show significant improvement in EF and functional capacity.
What is ejection fraction and why does it matter?
Ejection fraction (EF) is the percentage of blood the left ventricle pumps out with each heartbeat. A normal EF is 55–70%. An EF below 40% indicates significant weakness of the heart muscle (HFrEF) and guides treatment decisions. EF is measured using a 2D echocardiogram and is one of the most important numbers in heart failure management. Your cardiologist will track EF over time to assess whether treatment is working.
Can I exercise with heart failure?
Yes, and you should. Regular moderate exercise is safe and strongly recommended for most heart failure patients. Walking, light cycling and supervised cardiac rehabilitation improve exercise tolerance, reduce symptoms and decrease hospitalisation rates. The type and intensity of exercise should be discussed with your cardiologist based on your NYHA class and current stability. Avoid heavy weight lifting or intense exertion unless specifically cleared.
How long can you live with heart failure?
Life expectancy with heart failure varies widely and depends on the severity, cause, response to treatment and presence of other conditions. Many patients with mild to moderate heart failure (NYHA Class I–II) live for many years with a good quality of life on optimal medical therapy. Advances in treatment — particularly the four-pillar drug regimen, CRT and SGLT2 inhibitors — have significantly improved survival compared to two decades ago. The most important factors are early diagnosis, adherence to medications and regular follow-up.
What is the difference between a heart attack and heart failure?
A heart attack (myocardial infarction) is a sudden event where a coronary artery becomes blocked, cutting off blood supply to part of the heart muscle. Heart failure is a chronic condition where the heart gradually loses its ability to pump blood efficiently. A heart attack can cause heart failure if it damages enough heart muscle, but heart failure can also develop from other causes such as long-standing high blood pressure, valve disease or cardiomyopathy. Think of a heart attack as an acute emergency and heart failure as a long-term condition requiring ongoing management.
The Bottom Line
Heart failure is a serious but treatable condition. It does not mean the heart has stopped — it means the heart needs help. With timely diagnosis, guideline-directed medications (including the four pillars of ARNI, beta-blocker, MRA and SGLT2 inhibitor), appropriate device therapy and disciplined self-management, many patients experience significant improvement in symptoms, heart function and quality of life.
If you or a family member has been diagnosed with heart failure, or if you are experiencing symptoms such as unexplained breathlessness, persistent fatigue or ankle swelling, consult an experienced cardiologist who can assess your heart function and create a personalised treatment plan.
Related reading
About Dr. Abhinav Aggarwal
Dr Abhinav Aggarwal is an Interventional Cardiologist practising at CardioSight Clinic, Rohini, Delhi. He manages patients with heart failure, coronary artery disease and valvular heart disease at Fortis Hospital, Shalimar Bagh, providing comprehensive diagnosis, medical therapy and interventional procedures.
If you have been diagnosed with heart failure, need a review of your echocardiogram report, or want to understand your treatment options, a consultation can help you take the right next step.
Book an Appointment arrow_forwardThis article is intended for general patient education and does not replace a professional medical consultation. Heart failure management must be individualised based on your clinical condition, test results and response to treatment. Please discuss your specific situation with your cardiologist.