Irregular heartbeat

An irregular heartbeat means the rhythm is uneven — the beats come at varying intervals, or there is a sense of skipped, missed or extra beats — rather than the steady, regular tempo of a normal heart. This is different from a fast but regular pounding (a palpitation from exertion or anxiety); here the defining feature is the irregularity itself. The commonest cause is entirely benign: occasional extra beats (ectopic beats) arising early from the upper or lower chambers, felt as a skip or a thump, which most people have from time to time and which are usually harmless. But a sustained irregular pulse is the hallmark of atrial fibrillation, the most common significant heart rhythm disturbance, in which the upper chambers beat chaotically. Atrial fibrillation matters because it raises the risk of stroke and can be treated. Other rhythm disturbances, an overactive thyroid (which speeds and destabilises the rhythm), electrolyte imbalances (especially potassium and magnesium), caffeine, alcohol and some medications can all cause an irregular beat. Because a simple bedside pulse cannot distinguish harmless ectopics from atrial fibrillation, a persistently irregular heartbeat is best confirmed with an ECG.

• Occasional extra (ectopic) beats — the commonest cause; usually harmless, felt as a skip or thump.
• Atrial fibrillation — a sustained, irregularly irregular pulse; the most important cause to identify.
• Other abnormal heart rhythms — various, from benign to significant.
• Overactive thyroid — speeds and destabilises the rhythm.
• Electrolyte imbalances — especially low potassium or magnesium.
• Caffeine, alcohol, stimulants and some medications.
• Underlying heart disease — makes rhythm problems more likely.

An irregular heartbeat is confirmed and characterised with an ECG (and sometimes a longer recording, such as a 24-hour monitor, if it comes and goes) — this is what distinguishes harmless extra beats from atrial fibrillation. Blood tests support the assessment by looking for treatable drivers: thyroid function (TSH) for an overactive thyroid, potassium and magnesium for electrolyte imbalances, a full blood count for anaemia, and kidney function. Mediora.AI can surface a thyroid or electrolyte pattern from your results that may be contributing to an irregular rhythm, but the rhythm itself is diagnosed on an ECG, not from blood tests — a persistently irregular heartbeat is best assessed by your doctor with heart tracing.