Understanding Heart Failure: A Comprehensive Guide

Few diagnoses sound as frightening as heart failure. The name makes people imagine that the heart is about to stop, and that nothing can be done. In most cases, neither is true. Heart failure does not mean the heart has failed. It means the heart is not pumping as efficiently as it should, so it struggles to keep up with the demands of the body. It is a long-term condition, but with early diagnosis and modern treatment, many people live full and active lives for years.

In this guide I will explain what heart failure actually is, the first signs of a weak heart that you should not ignore, the main types and causes, how I diagnose it, and how we treat it today. The aim is to take some of the fear out of the word, and to make clear when you need to be seen.

What is heart failure?

The heart is a pump. With every beat it pushes oxygen-rich blood out to the muscles, brain, and organs. In heart failure, the pump can no longer do this job efficiently enough for the body’s needs. Either the heart muscle is too weak to squeeze out enough blood, or it has become too stiff to fill properly between beats.

When the heart falls behind, two things tend to happen. Less blood reaches the muscles, which is why people feel tired and breathless. And blood backs up behind the heart, so fluid leaks into the lungs and the legs. That fluid build-up is where the older term congestive heart failure comes from, and it explains most of the symptoms.

Heart failure is common, and it becomes more common with age. In Singapore it appears to affect a higher share of the population than in many Western countries, and people here often present at a younger age. That makes recognising it early all the more important.

What are the first signs of a weak heart?

Heart failure usually creeps up gradually rather than arriving all at once, which is why the early signs are so easy to brush off. The ones I want people to take seriously are:

• Breathlessness on exertion. Getting short of breath climbing stairs or walking up a slope when you used to manage it easily. As things progress, breathlessness can come on with less and less effort, and eventually even at rest.
• Waking up breathless at night. Two patterns matter here. Orthopnoea is breathlessness when lying flat, which is why people start propping themselves up on extra pillows. Paroxysmal nocturnal dyspnoea, or PND, is suddenly waking a few hours into sleep gasping for air and needing to sit up or stand at a window. Both are important clues that fluid is backing up into the lungs.
• Swelling of the ankles, feet, or legs. Gravity pulls retained fluid downwards, so the swelling is usually worst by the end of the day and eases overnight.
• Tiredness and reduced stamina. A persistent, unusual fatigue, because the muscles are not getting the blood flow they need.
• Rapid weight gain. Putting on weight over a few days, say one to two kilograms, is usually fluid, not fat. This is one of the most useful early warning signs to watch for at home.

Any one of these can have an innocent explanation. But if several appear together, or if they are getting worse, they deserve a proper assessment rather than a wait-and-see approach. New or rapidly worsening breathlessness, especially with swelling, should not be ignored.

What causes heart failure?

Heart failure is not really a disease in its own right. It is the end result of something else that has damaged or overloaded the heart. The common causes I see are:

• Coronary artery disease and previous heart attack. Narrowed or blocked heart arteries starve the heart muscle of blood. A heart attack can leave behind a patch of scarred, weakened muscle. This is the single most common cause of heart failure.
• High blood pressure. Years of hypertension force the heart to work against extra resistance. Over time the muscle thickens and stiffens, and eventually it can weaken. Well-controlled blood pressure is one of the most powerful ways to prevent heart failure. (See: the symptoms of high blood pressure.)
• Heart valve disease. A valve that is too tight or too leaky makes the heart work harder, and may eventually overwhelm it.
• Cardiomyopathy. Disease of the heart muscle itself, which can be inherited, follow a viral infection, or relate to alcohol and other causes.
• Abnormal heart rhythms. A persistently fast or chaotic rhythm, such as poorly controlled atrial fibrillation, can tire the heart muscle out over time.

Diabetes, obesity, and excess alcohol all add to the risk. In many patients more than one factor is at work at the same time.

What are the types of heart failure (HFrEF vs HFpEF)?

When I assess the heart, the key measurement is the ejection fraction, the percentage of blood the main pumping chamber pushes out with each beat. A normal ejection fraction is roughly 50 to 70 percent. This number splits heart failure into two broad types, and it matters because it guides treatment.

• Heart failure with reduced ejection fraction (HFrEF). Here the ejection fraction is 40 percent or below. The heart muscle is weakened and cannot squeeze out enough blood. This is the type for which we have the strongest, most life-changing medical treatments.
• Heart failure with preserved ejection fraction (HFpEF). Here the ejection fraction is 50 percent or higher, but the heart muscle has become stiff and does not relax and fill properly between beats. The pumping looks normal on the scan, yet the patient has all the symptoms of heart failure. This type is closely linked to high blood pressure, diabetes, and ageing.

There is also a middle group, mildly reduced ejection fraction, where the figure sits between 41 and 49 percent. Telling these types apart is one of the main reasons an echocardiogram is so central to diagnosis.

How is heart failure diagnosed?

Diagnosis starts with your story and a physical examination: the symptoms above, your medical history, and signs such as fluid in the lungs, a raised pulse in the neck, or swelling in the legs. From there I use a focused set of tests to confirm the diagnosis and find the cause.

• ECG (electrocardiogram). A quick recording of the heart’s electrical activity. It can show a previous heart attack, an abnormal rhythm, or a thickened heart muscle.
• Blood test for natriuretic peptides (BNP or NT-proBNP). When the heart is under strain it releases these hormones into the blood. A normal level makes heart failure unlikely, while a raised level points towards it and prompts further imaging. It is a genuinely useful first-line test.
• Echocardiogram. An ultrasound scan of the heart, and the single most important test. It measures the ejection fraction, shows how the chambers and valves are working, and helps separate the types of heart failure. It is painless and involves no radiation. (See: how to prepare for an echocardiogram in Singapore.)
• Further tests where needed. A chest X-ray, blood tests for the kidneys, thyroid, and iron levels, and sometimes more advanced imaging or an assessment of the coronary arteries to pin down the underlying cause.

The goal is to confirm whether this really is heart failure, work out which type it is, and identify what is driving it, because that is what shapes the treatment plan.

How is heart failure treated?

This is the part I most want people to hear, because heart failure treatment has been transformed over the past decade. For heart failure with reduced ejection fraction, modern guideline-directed therapy rests on what are often called the four pillars of medication. These are described here as drug classes rather than specific products:

1. ACE inhibitors, ARBs, or ARNIs, which relax blood vessels and reduce the strain on the heart.
2. Beta-blockers, which slow the heart and protect it over the long term.
3. Mineralocorticoid receptor antagonists (MRAs), which counter harmful hormonal effects and help the body shed excess fluid.
4. SGLT2 inhibitors, a newer class originally developed for diabetes that has been shown to help the failing heart as well.

Used together, these classes can ease symptoms, keep people out of hospital, and help them live longer. Diuretics (water tablets) are also used to relieve fluid build-up and breathlessness, although they treat the symptoms rather than the underlying problem. Treatment for HFpEF focuses on tight control of blood pressure and other conditions, with SGLT2 inhibitors now playing an important role here too. Because these are all prescription medicines, the right combination and doses must be tailored to you by your cardiologist. (See: our guide to navigating heart medications.)

In selected patients with a weak heart, device therapy can help. A cardiac resynchronisation therapy (CRT) device coordinates the contraction of the pumping chambers when they are beating out of step, and an implantable cardioverter defibrillator (ICD) guards against dangerous rhythm disturbances. Treating the root cause matters too, whether that means opening a blocked artery, repairing a valve, or controlling an abnormal rhythm.

Can heart failure be reversed or improved?

People often ask whether heart failure can be cured. For most, it is a long-term condition that is managed rather than cured outright. But “managed” sells it short, because the heart can genuinely improve. When the underlying cause is treated and the four pillars of medication are in place, the ejection fraction can recover substantially, sometimes back into the normal range. We even have a term for this, heart failure with improved ejection fraction.

The earlier treatment starts, the better the outlook tends to be. That is the real reason not to ignore the first signs of a weak heart. Importantly, even when the ejection fraction improves, the medications usually need to continue, because stopping them can allow the heart to weaken again.

Living with heart failure

Day-to-day habits make a real difference alongside medication. The measures I most often recommend are:

• Watch your salt and fluids. Too much salt makes the body hold on to water, which worsens swelling and breathlessness. Your cardiologist may suggest a daily fluid limit if needed.
• Weigh yourself regularly. A sudden gain of one to two kilograms over a few days usually means fluid is building up, and is a signal to seek advice early, often before you feel much worse.
• Keep moving. Gentle, regular exercise and a structured cardiac rehabilitation programme improve stamina and quality of life. Rest is not the answer for stable heart failure.
• Treat the risk factors. Stop smoking, keep blood pressure, diabetes, and cholesterol well controlled, and moderate alcohol.
• Stay on top of your medicines and reviews. Take medication as prescribed, and keep your follow-up appointments and vaccinations up to date.

To understand how heart failure sits alongside related problems, you may find our overview of common heart conditions helpful.

The bottom line

Heart failure is serious, but it is far from hopeless. It means the heart is not pumping efficiently, not that it is about to stop. The first signs, breathlessness on exertion, waking up short of breath, swollen ankles, unusual tiredness, and rapid weight gain, are your cue to get assessed rather than to panic. With an accurate diagnosis and modern treatment, symptoms can be controlled, hospital stays avoided, and the heart itself can often recover ground. The single most important step is acting early.

If you have noticed any of these signs, or you have a condition that puts your heart under strain, I provide comprehensive cardiac assessment at the Harley Street Heart and Vascular Centre in Singapore. Call +65 6235 5300 to arrange an appointment.

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Written by Dr Michael Ross MacDonald MB ChB, BSc (Hons), FRCP (UK), MD (Research), FESC (Europe) Senior Consultant Cardiologist at the Harley Street Heart and Vascular Centre, Singapore.

This article is general information, not a substitute for individual medical advice. If you are worried about your heart, seek medical care. If you have sudden severe breathlessness, chest pain, or you collapse, call 995 immediately.

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