I’m Dr Sohaib, a cardiologist in London, specialising in heart rhythm disorders. Heart palpitations are one of the most common reasons adults seek assessment by a cardiologist, particularly when symptoms are persistent, unpredictable, or affecting daily life.

Patients often worry that palpitations indicate a serious heart rhythm problem or heart condition. In reality, most heart palpitations are not dangerous and are commonly caused by benign rhythm changes. However, a small but important proportion are due to treatable heart rhythm problems which cannot always be distinguished based on symptoms alone.

A proper cardiology consultation and heart rhythm assessment is the most reliable way to determine whether palpitations are harmless or signs of underlying heart conditions.

What do heart palpitations feel like?

Patients describe palpitations in many different ways, including:

  • A racing heart rate or irregular heartbeat
  • A fluttering sensation in the chest
  • A sudden thump or jolt
  • A feeling the heart has skipped or missed a beat
  • Brief breathlessness or chest tightness
  • Dizziness or reduced exercise tolerance
  • Struggling more than usual with stairs or physical activity

Sudden episodes of rapid, regular palpitations that start and stop abruptly may be caused by a heart arrhythmia such as supraventricular tachycardia (SVT).

Some patients feel unwell enough to attend A&E for medical attention. Others only become aware of symptoms when a smartwatch flags an irregular heartbeat, prompting referral for further investigation.

The most common cause of palpitations: ectopic beats

The most frequent cause of heart palpitations is ectopic heartbeats, also known as extra beats.

Your heart has a natural pacemaker that normally controls your heartbeat. Occasionally, another area of the heart triggers an early, ectopic beat. This can create the sensation of:

  • A thud in the chest
  • A pause followed by a stronger beat
  • A brief feeling the heart has stopped and restarted

Although unsettling (and some patients may fear they are about to have a heart attack), ectopic beats are usually benign and do not indicate underlying heart disease.

If we monitored the heart rhythm of the general population for 24 hours, almost everyone would have at least a few ectopic beats.

Why do ectopic beats become noticeable?

Common causes of ectopic beats are:

  • Stress or anxiety (panic attacks)
  • Dehydration
  • Viral illnesses (including colds and flu)
  • Fatigue or poor sleep
  • Excessive caffeine consumption
  • Recreational drugs
  • Asthma inhalers

In many patients, palpitations fluctuate over time, prominent one year, barely noticeable the next.

When palpitations may indicate an abnormal heart rhythm or underlying heart problem

While most palpitations are harmless, in my experience around 1 in 10 people with unexplained palpitations are found to have a genuine heart rhythm problem, such as atrial fibrillation (AF) or supraventricular tachycardia (SVT). Rarely they can be related to a very serious heart rhythm problem, such has ventricular tachycardia (VT) or heart failure.

Occasionally, symptoms that sound like simple skipped beats turn out to be a significant heart problem. For this reason, reassurance should be evidence-based, supported by ECG testing and heart rhythm monitoring rather than assumption. I notably remember speaking to a young male patient who described a story which sounded typically like someone who might have ectopic beats, but when we did an ECG test, he was in atrial fibrillation! So rather than a benign condition which just needed some reassurance, he had a more significant issue which we eventually successfully treated with an ablation procedure.

Smartwatch alerts and irregular heart rhythms

Wearable devices and smartwatches are an increasingly common reason patients seek a private cardiologist for palpitations. I now regularly incorporate smartwatch data into my assessment of patients, along with more established tests.

Patients often request assessment because:

  • Their watch flagged an irregular heartbeat
  • Alerts are becoming more frequent
  • Symptoms correlate with recorded events

In some cases, smartwatch alerts are the first indication of and underlying heart condition, such as intermittent atrial fibrillation, or a problem with the heart muscle structure, which may otherwise go undetected. I now increasingly find that this is the first way many patients will discover they have a heart rhythm problem.

While smartwatches are helpful screening tools, they do not provide a diagnosis. A formal ECG and medical-grade heart rhythm monitoring remain essential. If you do receive an alert from your smartwatch, it is best not to ignore it and seek some clarification. Often this will just be reassurance, but occasionally it may be the first step in managing a heart rhythm abnormality. I discuss smartwatches and wearables in more detail in this blog.

When should palpitations be checked by a cardiologist?

You should consider seeing a cardiologist for medical advice if symptoms are:

  • Recurrent or worsening
  • Associated with breathlessness, dizziness, or blackouts
  • Associated with chest pain
  • Limiting exercise or daily activities
  • Newly developed after illness
  • Repeatedly flagged by a smartwatch
  • Causing ongoing anxiety or uncertainty

Even when the outcome is reassurance, most patients find significant relief in having a clear diagnosis and explanation.

How palpitations are usually investigated

A cardiology assessment for palpitations typically includes:

  • A detailed clinical history
  • ECG and blood pressure
  • Heart rhythm monitoring (24 hours or longer if required)
  • Echocardiogram to assess heart structure and function
  • Blood tests to exclude conditions such as hyperthyroidism

In most cases, these tests confirm a structurally normal heart.
In a smaller group, they identify a rhythm disorder that can be treated with medication, monitored, or managed appropriately.

Palpitations, dizziness, and autonomic conditions

Some patients experience palpitations alongside dizziness or blackouts due to autonomic conditions such as postural orthostatic tachycardia syndrome (POTS).

While symptoms can be distressing, they are often best managed through specialist autonomic care rather than heart rhythm procedures. A thorough cardiology assessment helps ensure patients are directed to the most appropriate pathway.

Key takeaway

Palpitations are common.
Most are harmless.
Some require treatment.

The difference cannot be reliably determined without proper assessment.
The aim is not to alarm — but to replace uncertainty with clarity.

What to do next

If you are experiencing ongoing palpitations and would like a clear, evidence-based explanation of what is happening, and whether any treatment is required, a specialist heart rhythm assessment with a private cardiologist in London can help.

If you have already been told you may have a rhythm condition, you may also find these pages helpful:

Frequently Asked Questions About Heart Palpitations

Are heart palpitations dangerous?
Most heart palpitations are not dangerous and are commonly caused by benign ectopic beats. A small proportion are due to rhythm disorders such as atrial fibrillation or SVT, which should be assessed by a cardiologist.

What do heart palpitations feel like?
Palpitations may feel like fluttering, pounding, a racing heartbeat, or the sensation that the heart has skipped a beat. Some people also experience breathlessness or dizziness.

Can stress or anxiety cause palpitations?
Yes. Stress, anxiety, dehydration, fatigue, and viral illnesses can all make palpitations more noticeable. Persistent or worsening symptoms should still be checked.

Should I worry about smartwatch alerts?
Smartwatch alerts are useful screening tools but are not diagnostic. Repeated alerts or alerts associated with symptoms should be investigated with ECG-based monitoring.

What tests are used to investigate palpitations?
Assessment usually includes an ECG, heart rhythm monitoring, and an echocardiogram to assess heart structure and function.