Breathlessness and heart failure — your questions answered

The single commonest cause of breathlessness on stairs is deconditioning — a fall in cardiovascular fitness from reduced activity. The next commonest are excess weight, anaemia and asthma. In older adults or those with risk factors, early heart failure, coronary disease and valve problems all need to be considered.

A useful distinction: deconditioning usually feels like a generalised tiredness and recovers within a few minutes of stopping. Cardiac breathlessness often comes with a heavier chest sensation, tends to be reproducible at the same level of exertion each time, and may be accompanied by ankle swelling or breathlessness when lying flat. A change in your usual exercise capacity over weeks or months always deserves assessment.

No — most breathlessness is not cardiac. Asthma, COPD, lung infections, anaemia, anxiety and deconditioning account for the majority of cases. Pulmonary embolus, asthma exacerbations and pneumothorax are important acute non-cardiac causes.

Heart-related breathlessness has recognisable features: it often worsens when lying flat (orthopnoea), wakes you in the night gasping (paroxysmal nocturnal dyspnoea), is associated with ankle swelling, comes on with predictable exertion, or is accompanied by an irregular pulse. If any of these apply, a cardiology assessment is worthwhile even if a respiratory cause has already been suggested.

Heart failure is a clinical syndrome in which the heart cannot pump enough blood to meet the body's needs, or can only do so at the cost of high filling pressures. The name is misleading — the heart has not "failed" in the dramatic sense; it is underperforming, and the body responds with fluid retention, breathlessness and fatigue.

Some forms are reversible — alcohol-related cardiomyopathy that improves with abstinence, or tachycardia-induced cardiomyopathy that recovers once the rhythm is controlled. Most chronic heart failure is not fully reversible, but modern treatment can substantially improve symptoms, quality of life, hospitalisations and survival — often dramatically.

In selected cases, yes — but more commonly heart failure is controlled rather than cured, similar to high blood pressure or diabetes. Reversible causes — alcohol, untreated arrhythmia, severe valve disease, certain inflammatory conditions — can sometimes be fully treated and the heart muscle can recover.

For most patients, the modern combination of "the four pillars" of heart failure medication — an ACE inhibitor or sacubitril-valsartan, a beta-blocker, a mineralocorticoid antagonist and an SGLT2 inhibitor — plus device therapy where appropriate and lifestyle change provides excellent symptom control and substantially improves life expectancy. The earlier treatment starts, the better the outcome.

Ankle swelling has many causes: prolonged standing or sitting, hot weather, pregnancy, varicose veins, certain medications (calcium channel blockers, some painkillers), kidney or liver problems, and venous insufficiency. Heart failure is an important cause but not the most common.

Cardiac ankle swelling is usually bilateral (both legs), worse by evening, pits when you press it, and is accompanied by breathlessness on exertion, breathlessness when lying flat, or fatigue. Sudden one-sided leg swelling needs immediate assessment to exclude a deep vein thrombosis. New, unexplained bilateral ankle swelling with any breathlessness should prompt a cardiac review.

Modern outcomes are much better than older statistics suggest, and life expectancy varies enormously depending on the cause, severity, treatments received and the patient's other health conditions. Some forms of heart failure recover fully; others remain stable for decades with treatment.

With the current four-pillar drug regimen, well-managed mild-to-moderate heart failure carries a five-year survival approaching that of many cancers in remission, and many patients live normal-length lives. The single most important factor in outcome is starting full guideline-directed treatment early and at the correct doses. Outdated prognostic statistics do not reflect today's reality.

Yes — breathlessness is one of the commonest symptoms of atrial fibrillation, particularly when the heart rate is fast. AFib reduces the efficiency of each heartbeat by around 20–30%, and a sustained fast rate over weeks or months can weaken the heart muscle and cause heart failure — so-called tachycardia-induced cardiomyopathy.

The good news is that this form of heart failure usually reverses once the rhythm or rate is controlled. Any new breathlessness combined with an irregular pulse should be investigated promptly — for the AFib itself, which has implications for stroke risk, and for the impact on heart function.

The standard work-up combines an ECG, blood tests including NT-proBNP (a highly sensitive heart failure marker), thyroid function, full blood count and kidney function, a chest X-ray, and an echocardiogram. This combination identifies the cause in the majority of patients.

If the diagnosis remains unclear, further tests may include cardiac MRI, lung function tests, CT coronary angiogram or cardiopulmonary exercise testing (CPET) — the gold-standard test for distinguishing cardiac from respiratory limitation and quantifying true exercise capacity.

Persistent breathlessness after a COVID infection is common — affecting up to a fifth of people in the months after acute illness — and most cases improve gradually over 3 to 12 months.

A small proportion of post-COVID breathlessness reflects ongoing lung scarring, myocarditis (heart muscle inflammation), pulmonary embolus, or post-viral autonomic dysfunction (POTS). New breathlessness persisting beyond 12 weeks, or breathlessness with chest pain or palpitations, deserves a cardiac assessment including an ECG, echocardiogram and often cardiac MRI.

The two terms overlap but are not identical. A "weak heart" colloquially means reduced pumping function — what cardiologists call reduced ejection fraction (HFrEF). Heart failure is the clinical syndrome that follows when pumping function is inadequate for the body's needs.

Importantly, heart failure can also occur with a preserved ejection fraction (HFpEF) — the heart pumps normally but is stiff and cannot relax properly, so filling pressures rise and fluid backs up. HFpEF is increasingly recognised, particularly in older patients, women and those with hypertension or obesity. Both forms cause similar symptoms and both have evidence-based treatments.