What Can Cause an Irregular or Erratic Pulse?

Noticing that your heart seems to be beating unevenly, skipping beats, or racing without obvious cause can feel alarming. An irregular or erratic pulse is a symptom that many people encounter at some point, and while it often has a straightforward explanation, it can also point to an underlying heart-rhythm disorder that warrants further investigation. Understanding the range of possible causes — and knowing when to seek appropriate advice — is an important first step.

Quick Answer: What Causes an Irregular Pulse?

An irregular or erratic pulse can result from a broad range of causes, including lifestyle factors, stress, stimulants, thyroid imbalance, anaemia, or a heart-rhythm disorder such as atrial fibrillation. Irregular pulse causes vary considerably between individuals. A clinical assessment — including a review of symptoms, medical history and relevant tests — may be needed to identify the cause and determine whether further investigation is appropriate.

Medical assessment may be appropriate if your irregular pulse:

Is new, persistent or becoming more frequent
Occurs during or after physical activity
Is accompanied by breathlessness, dizziness or chest discomfort
Causes fainting or near-fainting
Is associated with a notably fast or very slow heartbeat
Is causing significant concern or affecting daily life

Symptoms alone cannot confirm or exclude a cardiovascular condition. A clinical assessment is required to determine the cause.

What Does an Irregular Pulse Actually Mean?

The pulse is a reflection of the heart's rhythm. Each beat of the heart corresponds to a pressure wave felt at the wrist, neck or other pulse points. In a healthy resting heart, these beats occur at a regular, steady rhythm — typically between 60 and 100 beats per minute in adults, according to NHS guidance.

An irregular pulse — sometimes described as palpitations, a racing heart, a fluttering sensation in the chest, skipped beats, or a heart that seems to "thump" unexpectedly — can feel quite different from person to person. Some people notice it only occasionally; others experience it frequently or continuously.

The irregularity may involve:

Extra or ectopic beats — isolated beats that feel like a thump or skip
A persistently irregular rhythm — where the heart beats in no consistent pattern
Episodes of fast heart rate — where the pulse suddenly races
Slow or pausing beats — where the heart appears to hesitate

Not all of these patterns carry the same clinical significance, but distinguishing between them is something only a clinical assessment can reliably achieve. For individuals concerned about erratic pulse symptoms that cardiologists investigate, a specialist review may help clarify the cause.

When Could an Irregular Pulse Be Related to the Heart?

An irregular pulse does not automatically mean a heart problem exists, but several cardiac conditions are known to produce rhythm disturbances. When the irregularity is persistent, recurrent, or accompanied by other symptoms, a cardiac cause deserves careful consideration.

Atrial Fibrillation (AF)

Atrial fibrillation is one of the most commonly diagnosed heart-rhythm disorders in the United Kingdom. In AF, the upper chambers of the heart (the atria) beat chaotically and out of sync with the lower chambers. This produces a characteristically irregular and often fast pulse. AF may be persistent, paroxysmal (coming and going), or permanent.

The British Heart Foundation notes that AF affects around 1.4 million people in the UK, and many are unaware they have it. It increases the risk of stroke, which is why timely diagnosis and management matter.

Ectopic Beats

Ectopic beats — sometimes called premature atrial contractions (PACs) or premature ventricular contractions (PVCs) — are extra beats that disrupt the normal rhythm. They are often felt as a "skipped" beat or a brief, heavy thump. In many cases they are benign, but frequent or complex ectopic beats may warrant further assessment.

Other Heart-Rhythm Disorders

Other rhythm conditions that can produce an irregular or erratic pulse include:

Supraventricular tachycardia (SVT) — episodes of rapid heart rate originating above the ventricles
Ventricular tachycardia — a fast rhythm originating in the lower chambers, which may be more serious
Heart block — where the electrical signals within the heart are delayed or interrupted
Sick sinus syndrome — where the heart's natural pacemaker malfunctions

Structural Heart Conditions

Conditions affecting the structure of the heart — including cardiomyopathy, heart valve disease and heart failure — can also predispose individuals to rhythm disturbances. These typically require specialist investigation.

Other Possible Explanations for an Irregular Pulse

Not every irregular or erratic pulse has a cardiac origin. Several non-cardiac factors can disrupt the heart's rhythm or create the sensation of an irregular heartbeat.

Lifestyle and physiological factors include:

Caffeine and stimulants — high intake of coffee, energy drinks, or certain supplements can trigger palpitations
Alcohol — both acute consumption and longer-term excessive intake can disturb heart rhythm
Dehydration — particularly in warmer weather or after exercise
Lack of sleep — poor sleep quality is associated with rhythm disturbances
Anxiety and stress — the physiological response to stress can increase heart rate and cause palpitations
Strenuous physical activity — particularly in those who are deconditioned or who overexert

Medical conditions that may contribute include:

Thyroid disorders — an overactive thyroid (hyperthyroidism) commonly causes a fast or irregular pulse
Anaemia — low iron or haemoglobin levels can cause the heart to beat faster or less regularly
Fever or infection — these raise heart rate and may produce irregular beats
Low potassium or magnesium — electrolyte imbalances can affect the heart's electrical system
Certain medications — some prescription and over-the-counter medicines can influence heart rhythm

It is important not to use a non-cardiac explanation to dismiss a symptom that requires proper assessment. The cause should be established through clinical evaluation, not assumption.

Cardiovascular Risk Factors Worth Being Aware Of

Certain factors increase the likelihood that an irregular pulse may have a cardiac origin. These do not confirm heart disease, but they add context that a clinician will consider.

Relevant risk factors include:

Age — the risk of AF and other rhythm disorders increases with age
High blood pressure (hypertension) — a leading risk factor for AF and other cardiac conditions
High cholesterol — contributes to coronary artery disease, which can affect heart rhythm
Diabetes — associated with increased cardiovascular risk
Obesity — linked to a higher incidence of AF and other rhythm problems
Obstructive sleep apnoea — strongly associated with atrial fibrillation
A family history of heart disease — particularly early-onset rhythm disorders or sudden cardiac events
Smoking — damages blood vessels and can affect heart rhythm
Excessive alcohol consumption — a recognised trigger for AF, sometimes called "holiday heart"

Having none of these risk factors does not completely exclude a cardiac cause. Individual risk should always be interpreted by an appropriate clinician.

When Cardiovascular Screening May Be Useful

For individuals without symptoms but who have concerns about their heart health or wish to understand their cardiovascular risk profile, health screening may offer a useful starting point.

Private Doctor London provides private testing and health screening services, which may include:

Blood pressure measurement
Cholesterol and lipid profile testing
Blood sugar and HbA1c testing — to assess for diabetes or pre-diabetes
Cardiovascular risk scoring — using validated tools to estimate overall risk
Resting ECG testing (where available) — to assess the heart's baseline electrical activity

Screening can identify possible risk factors or findings that may require further attention. However, it does not replace medical assessment when someone has symptoms or feels unwell, and it cannot diagnose or exclude a heart-rhythm disorder. Results are reviewed by GMC-registered doctors.

Please note: Private Doctor London provides private testing and health screening. It does not provide general GP consultations, specialist cardiology consultations, cardiac treatment or emergency care.

When Specialist Cardiology Assessment May Be Appropriate

Some presentations warrant assessment by a consultant cardiologist rather than — or in addition to — a screening test. A specialist assessment can provide a far more detailed evaluation than a resting ECG or cardiovascular risk check alone.

Situations in which a specialist cardiology assessment may be appropriate include:

A new, persistent or frequently recurring irregular pulse
Palpitations associated with breathlessness, chest discomfort or dizziness
Episodes of fainting or near-fainting in connection with an irregular heartbeat
Palpitations that occur during physical activity
A resting ECG showing an abnormal rhythm
A family history of arrhythmia, cardiomyopathy or unexplained sudden death
Concerns about an existing heart condition

A private specialist cardiology assessment by Dr Ravi Assomull at Cardiologist London can provide a structured clinical evaluation of rhythm symptoms, tailored to the individual's history and presentation.

Tests a Cardiologist May Consider

The investigations recommended for an irregular or erratic pulse depend on the clinical picture — including symptom frequency, severity, associated features and risk factors. A cardiologist will determine which tests are appropriate after taking a detailed history and performing a clinical examination.

Investigations that may be considered include:

Electrocardiogram (ECG)

A resting ECG records the heart's electrical activity over a short period. It can detect an abnormal rhythm if it is present at the time of the recording. However, a single normal resting ECG does not exclude every rhythm disorder, particularly those that occur intermittently.

Ambulatory ECG Monitoring

Because many rhythm disturbances are intermittent, an ambulatory ECG monitor for detecting intermittent heart rhythm problems — such as a 24-hour, 48-hour or longer Holter monitor — records the heart rhythm continuously over an extended period. This significantly increases the chance of capturing an abnormality that a brief resting ECG might miss.

Echocardiogram

An echocardiogram uses ultrasound to produce detailed images of the heart's structure and function. It can identify structural abnormalities — such as valve disease or cardiomyopathy — that may predispose to rhythm disturbances.

Exercise ECG (Stress Test)

An exercise ECG monitors the heart's rhythm and electrical activity during physical exertion. It may be considered when symptoms occur predominantly during or after activity.

Blood Tests

Targeted blood tests — including thyroid function, full blood count, electrolytes and kidney function — can identify non-cardiac causes of an irregular pulse, such as thyroid disease or anaemia.

Further Cardiac Imaging

In some cases, cardiac MRI or CT coronary angiography may be recommended if a structural or coronary cause is suspected. These are specialist investigations that require clinical justification.

Not all individuals will require every investigation. A clinician should advise on the most appropriate pathway based on clinical assessment.

Supporting Long-Term Heart Health

Whilst the cause of an irregular pulse should always be professionally evaluated, several evidence-based lifestyle habits are broadly recognised to support cardiovascular health:

Avoiding or reducing caffeine — particularly if palpitations coincide with high intake
Moderating alcohol consumption — excessive alcohol is a recognised trigger for AF
Not smoking — smoking damages the cardiovascular system and increases arrhythmia risk
Maintaining a healthy weight — obesity is linked to a higher risk of AF
Getting adequate, consistent sleep — and seeking assessment for sleep apnoea if relevant
Managing stress — through appropriate psychological support, physical activity or relaxation techniques
Staying well hydrated — particularly during hot weather or exercise
Taking prescribed medication as directed — and discussing any concerns with the clinician responsible for your care

Individuals with existing heart conditions or significant symptoms should seek appropriate clinical advice before making substantial changes to their diet or exercise routine.

When to Seek Emergency Help

Call 999 immediately if you experience:

Sudden or severe chest pain or pressure that does not settle
Chest discomfort spreading to the arm, jaw, neck, back or stomach
A very fast or irregular heartbeat accompanied by chest pain, collapse or severe breathlessness
Fainting or loss of consciousness
Sudden severe breathlessness
Sudden weakness or numbness on one side of the body
Facial weakness, slurred speech or difficulty finding words

These may be signs of a medical emergency. Do not drive yourself. Do not search for a private appointment. Call 999 immediately.

For symptoms that are concerning but not immediately life-threatening — for example, a new irregular pulse that is not accompanied by collapse or chest pain — NHS 111 can provide urgent guidance on next steps.

Frequently Asked Questions

Can stress or anxiety cause an irregular pulse?

Yes. The physiological stress response releases adrenaline, which can increase heart rate and trigger ectopic beats or palpitations. However, stress is not the only possible cause, and symptoms should be assessed clinically rather than attributed to anxiety without proper evaluation — particularly when they are new, frequent or accompanied by other features.

When should I see a cardiologist about an irregular heartbeat?

Consider a specialist assessment if the irregular pulse is new, persistent, recurring frequently, associated with breathlessness, dizziness, chest discomfort or fainting, or if a resting ECG has shown an abnormal result. A cardiologist can review symptoms in detail and recommend appropriate investigations.

Can a normal ECG rule out atrial fibrillation or other rhythm disorders?

Not reliably. A resting ECG only records the heart's rhythm at one point in time. If an arrhythmia is intermittent — as AF often is — it may not be present during the recording. Ambulatory ECG monitoring over a longer period increases the chance of detecting an irregular rhythm.

Should I seek advice even if the symptoms have gone away?

Yes, if symptoms were significant, recurring or accompanied by other features such as breathlessness or dizziness. An irregular pulse that has resolved may still warrant investigation, particularly if it was prolonged or caused loss of consciousness. A clinician can advise whether further assessment is needed.

Are there lifestyle factors that commonly trigger an irregular pulse?

Yes. Caffeine, alcohol, sleep deprivation, dehydration and stress are among the most commonly reported triggers. Certain medications and stimulant supplements can also contribute. Identifying and modifying known triggers can be helpful, but lifestyle changes should complement — not replace — clinical assessment.

Do I need a GP referral to see a private cardiologist?

Not always. Private cardiology services can often be accessed directly without a GP referral. However, it is worth discussing persistent or new symptoms with a healthcare professional, as they may provide relevant background information useful to a specialist. Availability and access routes should be confirmed directly with the specialist provider.

Private Cardiology Information in London

If you have non-emergency symptoms that are persistent, recurrent, or affecting your quality of life, an appropriate healthcare professional can advise whether a specialist cardiovascular assessment would be beneficial. Information on private atrial fibrillation diagnosis and treatment options in London is published by a specialist cardiology provider, including services associated with Dr Ravi Assomull. Current services and appointment availability should be confirmed directly with the provider.

Medical Disclaimer

This article is for general informational purposes only and does not constitute medical advice, diagnosis or treatment. Cardiovascular symptoms can have several possible causes and should be assessed according to individual circumstances. Seek advice from an appropriate healthcare professional if symptoms are persistent, recurrent or worsening. Call 999 immediately if you experience symptoms of a possible heart attack, stroke or another medical emergency. Private Doctor London provides private testing and health screening but does not provide general GP consultations, specialist cardiology consultations, cardiac treatment or emergency care.