Atrial fibrillation and shortness of breath

In atrial fibrillation, the upper heart chambers beat irregularly and the pulse may be fast, slow or variable. The lower chambers may then fill less effectively, particularly during activity. This can cause breathlessness, tiredness, reduced stamina, dizziness or palpitations. Symptoms may come and go or persist.

Breathlessness has many possible explanations, so the symptom alone cannot establish that atrial fibrillation is responsible. A clinician may assess for heart failure, angina, anaemia, asthma or another lung problem. The timing, pulse, oxygen level, examination and an electrocardiogram help distinguish among causes.

Stop strenuous activity, sit upright and notice whether the breathlessness settles. If you have known atrial fibrillation, follow the action plan given by your care team and take medicines exactly as prescribed. Do not take an extra heart-rate dose unless a clinician has specifically instructed you to do so.

Arrange assessment for new, recurring or worsening breathlessness. Note when it began, what you were doing, whether lying flat makes it worse, and whether it occurs with chest discomfort, cough, swelling, fever, wheeze or a racing pulse. Bring any home pulse or blood-pressure readings and your medicine list.

Call emergency services if breathing is severe or rapidly worsening, occurs with chest pressure, fainting, blue or grey lips, confusion, heavy sweating or an inability to speak comfortably. Sudden breathlessness with facial swelling, hives or throat tightness also needs emergency help. Do not drive yourself if you feel faint or cannot breathe comfortably.

Clarify whether symptoms match the recorded heart rhythm, whether heart imaging or blood tests are needed, and what pulse range should prompt contact. Ask how each medicine helps, whether rhythm or rate control is the current goal, and which activities are suitable while the cause of breathlessness is being assessed.