What should you know about extreme heart palpitations?

Palpitations are an awareness of your heartbeat. They may feel forceful, rapid, fluttering or as though a beat has been missed. Stress, poor sleep, caffeine, nicotine, fever, dehydration and low blood sugar can trigger them. Anaemia, iron deficiency anaemia, an overactive thyroid and atrial fibrillation are among the health conditions that can present with palpitations; a palpitation does not by itself identify the cause.

A clinician may ask when the episode began, how long it lasted, whether the rhythm felt regular, and what you were doing. They may check your pulse, blood pressure and heart rhythm and arrange an electrocardiogram or blood tests.

Stop exertion and sit somewhere cool and safe. Breathe slowly, loosen tight clothing, and avoid caffeine, nicotine, alcohol and decongestants until the sensation settles. If you may be dehydrated, take small sips of water unless a clinician has told you to limit fluids. Note the start time, possible trigger, pulse pattern and associated symptoms; this record can help with assessment.

Seek emergency help for palpitations with chest pressure, severe shortness of breath, fainting, new confusion, marked weakness or a sustained very irregular heartbeat. Arrange prompt medical review when episodes keep returning, occur with exertion, or are becoming stronger. Do not drive yourself if you feel faint or unwell.

Could a heart rhythm problem, thyroid disorder, anaemia or dehydration explain this pattern? Do I need an electrocardiogram, blood tests or monitoring? Which medicines, supplements or stimulants should I avoid, and what should I do if the episode returns?