What should you know about bradycardia shortness of breath?

Bradycardia is a slower-than-expected heart rate. If the heart cannot increase its output when the body needs more oxygen, breathlessness, tiredness or reduced exercise tolerance may occur. A slow pulse can also be a normal finding in some people, so the context matters. Other causes of shortness of breath include asthma, acute bronchitis, COPD, bronchiectasis, anaemia, angina, atrial fibrillation and allergic reactions such as anaphylaxis. The symptom alone cannot identify which condition is responsible.

Stop and rest when breathlessness begins, sit upright and note the pulse, breathing symptoms, activity and any medicines taken. Arrange a clinical review for new or recurring episodes. The clinician may check oxygen level, heart rhythm, lungs and blood tests, depending on the history. Continue prescribed treatment unless told otherwise, and do not use someone else’s inhaler or heart medicine. Avoid strenuous exertion until a clinician has advised you how to proceed if episodes are unexplained.

Call emergency services for severe or rapidly worsening breathlessness, blue or grey lips, inability to speak in full sentences, fainting, new confusion, severe chest pain or signs of anaphylaxis such as facial swelling and difficulty swallowing. Urgent assessment is also needed if breathlessness follows a sudden collapse, occurs at rest or comes with a markedly irregular heartbeat. Do not drive yourself if you feel faint or severely unwell.

Could my slow pulse explain the breathlessness, or is a lung condition also possible? Which tests would clarify the cause? Are any medicines affecting my heart rate, and what should I do if the episode returns?