Why Does My Heart Skip a Beat?

The sensation of your heart skipping a beat is almost always caused by an ectopic beat, an extra heartbeat that arrives slightly early and briefly disrupts your normal rhythm. What you actually feel as a "skip" is usually the short pause that follows the early beat, then the next beat landing harder than usual because the heart has had extra time to fill. Ectopic beats are extremely common, happen in almost everyone at some point, and in the vast majority of cases are completely harmless. Other causes of a skipping or irregular sensation include atrial fibrillation and other rhythm disturbances, which is why a symptom that recurs or comes with other signs is worth checking.

If you've been searching because it keeps happening and you want to know whether it's serious, here's the short version. Occasional skipped beats, particularly when you're tired, stressed, or have had caffeine or alcohol, are normal and rarely need treatment. Skipped beats that come in frequent runs, that arrive with breathlessness, dizziness, chest discomfort, or fainting, or that occur against a background of known heart disease or a family history of sudden cardiac death, deserve a proper assessment. The company the symptom keeps matters far more than the skipped beat on its own.

What a Skipped Beat Actually Is

Your heart normally beats in a steady, coordinated rhythm driven by its own electrical system. An ectopic beat is triggered early by a small patch of heart tissue firing off ahead of schedule. There are two main types. Premature atrial contractions start in the upper chambers, and premature ventricular contractions start in the lower chambers. Both are common, and both usually feel the same to the person experiencing them.

The odd thing is that people rarely feel the early beat itself. What registers is the compensatory pause afterwards and then the forceful beat that follows, which many describe as a thud, a flip, or the heart "turning over". The British Heart Foundation's information on ectopic beats explains the mechanism in more detail.

The Most Common Triggers

Ectopic beats are strongly influenced by lifestyle and circumstance. The usual triggers are:

Caffeine. Coffee, tea, energy drinks, and even dark chocolate can provoke ectopics in sensitive people.

Alcohol. A well-recognised trigger, particularly the morning after heavier drinking.

Stress and anxiety. Raised adrenaline makes the heart's electrical system more excitable. The NHS guidance on anxiety covers the physical symptoms.

Tiredness and poor sleep. Sleep deprivation lowers the threshold for ectopic beats.

Nicotine. A stimulant that increases ectopic frequency.

Dehydration and electrolyte imbalance. Low potassium or magnesium can make ectopics more frequent.

Hormonal changes. Many women notice more skipped beats around their period, in pregnancy, or during perimenopause.

An overactive thyroid. This raises the heart's excitability. The NHS information on an overactive thyroid outlines the wider symptoms.

From working with patients across South West London and the South-East over the past decade, we've found that a large proportion of people who come in worried about skipped beats can trace the pattern to two or three specific triggers, most often caffeine and disrupted sleep. Around 80% of the skipped-beat presentations we assess turn out to be benign ectopic beats with no underlying structural problem, once we've done the appropriate checks.

When a Skipped Beat Points to Something More

The cardiac causes worth ruling out are less common but more important to catch.

Atrial fibrillation. Atrial fibrillation produces an irregular, sometimes chaotic pulse rather than the occasional isolated skip, and it raises stroke risk if left untreated. Some patients first describe it as "skipping" before the irregularity becomes more constant. The NHS information on atrial fibrillation explains why it needs proper management.

Other arrhythmias. Tachycardia and conduction problems such as heart block can produce irregular or dropped beats, and the palpitations they cause sometimes overlap with the skipping sensation.

A high ectopic burden. Even when ectopics are benign in type, a very high frequency can occasionally strain the heart over time and needs monitoring.

Structural heart disease. In patients with existing coronary heart disease or heart failure, frequent ectopics carry more significance and warrant closer attention.

In our experience, the single most reassuring feature is whether the skipped beats disappear during exercise. Benign ectopics typically settle as the heart rate rises, whereas ectopics that become more frequent with exertion are the ones we look at more carefully.

When to Seek Help

Arrange a cardiology assessment if you experience:

• Frequent or persistent skipped beats rather than the occasional one

• Skipping that comes with chest pain, breathlessness, or dizziness

• Fainting or near-fainting alongside the sensation

• An irregular pulse that doesn't settle

• Known heart disease or a family history of arrhythmia or sudden cardiac death

The NHS guidance on heart palpitations is a sensible starting point if you're trying to gauge urgency. Skipped beats accompanied by chest pain in particular should be assessed promptly, as chest discomfort has its own range of cardiac causes.

How We Investigate Skipped Beats at Heartsure

Across more than a decade of running diagnostic cardiology in Kingston-upon-Thames, we've completed in excess of 12,000 cardiac investigations, and skipped beats are one of the most common reasons people self-refer. A first appointment combines a detailed history, a consultant assessment, and a 12-lead ECG. The NHS overview of ECGs explains how the test works for anyone who hasn't had one.

Because a resting ECG only records around 10 seconds, and skipped beats are intermittent by nature, most patients need extended monitoring. We use a wearable ECG monitor recording for up to seven days, which captures the rhythm at the exact moment the symptom occurs. Where structural disease is a possibility, an echocardiogram assesses the heart's chambers and valves, and bloods through our diagnostic blood testing service check thyroid function and electrolytes. If a rhythm is provoked by exertion, an exercise tolerance test can reproduce it under controlled conditions.

In our experience, quantifying the ectopic burden over a full week works better than a one-off recording because it tells us not simply whether ectopics are present, but what proportion of the total heartbeats they make up. That figure is what actually determines whether reassurance or treatment is the right answer, and we've found that most patients worried about skipped beats have a burden well under 1%, which is firmly in the benign range and often more reassuring to see written down than any verbal explanation.

Practical Steps to Take Before Your Appointment

A few simple things help us reach an answer faster.

Keep a symptom diary for two weeks, noting the time of each episode, what you'd eaten or drunk, your caffeine and alcohol intake, and your sleep and stress levels. Track your heart rate on a smartwatch if you have one, since several modern devices now record a single-lead ECG trace that we can corroborate. Try cutting caffeine and alcohol for a fortnight, because if the skipping eases, you've already identified a trigger, and if it doesn't, that narrows the picture. Finally, note any family history of rhythm problems or sudden cardiac death, as this shifts our diagnostic priority.

Conclusion

A heart that skips a beat is, in the great majority of cases, experiencing harmless ectopic beats driven by caffeine, alcohol, stress, tiredness, or hormones. But because a small proportion of skipping sensations reflect atrial fibrillation or another rhythm problem, and because frequent ectopics occasionally matter in their own right, a persistent or worsening pattern deserves a proper assessment rather than guesswork. The right combination of consultation, ECG, extended rhythm monitoring, and where needed an echocardiogram gets most patients to a confident, and usually reassuring, answer quickly.

If your heart has been skipping beats and you want to understand why, you can contact Heartsure on 0208 255 5999, email info@heartsure.co.uk, get in touch through our contact page, or book an appointment online. Our team in Kingston-upon-Thames offers same-day appointments where clinically appropriate, and most patients are seen within the same week as their first enquiry.