Medically reviewed by Dr Nabila Laskar, Consultant Cardiologist (GMC 7040901). Breathlessness (dyspnoea) is a common symptom with many possible causes — from lung conditions and anaemia to deconditioning and anxiety. But when the heart is the source, identifying it early matters, because cardiac breathlessness often signals a condition that is treatable if caught in time.
The heart and lungs work as an integrated system. When the heart doesn't pump efficiently, fluid backs up into the lungs, causing breathlessness. The most common cardiac causes include heart failure (reduced pumping function), valve disease (particularly mitral or aortic valve problems), arrhythmias (irregular heart rhythms that reduce efficiency), and pericardial effusion (fluid around the heart). Coronary artery disease can also cause breathlessness as an angina equivalent, particularly in women.
Sudden severe breathlessness at rest, breathlessness accompanied by chest pain or palpitations, waking from sleep unable to breathe, or swelling in the legs alongside breathlessness — all of these warrant urgent cardiac assessment, not a routine appointment.
Assessment starts with a detailed clinical history — crucially, whether breathlessness occurs at rest or only on exertion, whether it is new or longstanding, and whether it is worsening. An ECG identifies rhythm problems. An echocardiogram directly assesses heart muscle function, valve performance, and any fluid collection — it is the single most informative test for cardiac breathlessness. Blood tests including BNP (a cardiac stress marker) help quantify the degree of cardiac strain.
Breathlessness on exertion is frequently dismissed as 'just being unfit,' particularly in women and in people who are otherwise well. This attribution delays diagnosis of genuinely cardiac causes. Any progressive or unexplained breathlessness deserves formal assessment.
Clinical assessment, ECG, echocardiogram and sometimes lung function testing together help distinguish cardiac from respiratory causes. Neither you nor your GP can reliably tell from symptoms alone — specialist assessment is needed.
Yes, anxiety commonly causes breathlessness and even chest tightness. However, cardiac causes should always be formally excluded before attributing symptoms to anxiety, particularly in anyone over 35 or with risk factors.
Mild breathlessness on exertion is normal in the deconditioned. But new or worsening breathlessness on activities you previously managed easily warrants assessment.
BNP (B-type natriuretic peptide) is a blood marker released when the heart is under stress. Elevated BNP levels point toward a cardiac cause of breathlessness and help guide the urgency of further investigation.