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Health condition · Clinically reviewed

Bradycardia, when a slow heart is fine, and when it needs a pacemaker.

A rate below 60 bpm can be an athlete’s baseline or the first sign of conduction disease. The story is in the symptoms, the ECG and the rhythm strip.

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Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a UK cardiologist before publication.

  • 02

    Sourced from guidance

    Checked against ESC 2021 pacing guidance, BHRS standards and peer-reviewed sources you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK practice including leadless pacing, implantable loop recorders and remote device follow-up.

Key facts

Bradycardia at a glance.

The essentials, in plain English: what it is, the common causes, and how UK cardiology decides who needs a pacemaker.

  • What it is

    A heart rate below 60 beats per minute at rest, which can be a normal physiological finding or a sign of conduction disease.

  • Physiological

    Well-conditioned athletes may sit at 40 to 50 bpm at rest, and everyone slows in sleep and after a vasovagal event.

  • Where the problem sits

    Sinus node disease, AV node or His-Purkinje conduction block, fascicular block, or medications and metabolic causes.

  • Symptoms to watch

    Fatigue, light-headedness, presyncope, syncope, exercise intolerance, breathlessness, falls and confusion.

  • Foundation of assessment

    A 12-lead ECG, longer rhythm monitoring where symptoms are intermittent, and a medication review.

  • Definitive treatment

    Treat the underlying cause where possible, and consider permanent pacing per ESC 2021 for symptomatic or high-grade block.

Why this guide matters

The rate is a clue, not a diagnosis.

Bradycardia can be normal physiology, a drug effect, or a sign of conduction disease. The three points below shape everything else on this page.

  • Symptoms trump numbers

    A trained athlete at 45 bpm is fine; a symptomatic adult at 50 bpm may need a pacemaker. Context and symptoms decide.

  • The ECG tells the story

    Sinus node dysfunction, first, second and third-degree AV block, and fascicular block each have distinctive ECG patterns and prognoses.

  • ESC 2021 sets the pacing bar

    European Society of Cardiology guidance codifies who benefits from a pacemaker and when a leadless or CRT device is preferred.

How the diagnosis is made

From first ECG to a clear plan.

The steps a UK GP, acute physician or cardiologist will normally follow, in order, so you know what to expect and why.

  1. 01

    Assessing

    History and symptom mapping

    A structured look at fatigue, presyncope, syncope, exercise tolerance, falls and any Stokes-Adams attacks.

  2. 02

    Assessing

    12-lead ECG

    Rate, rhythm, PR interval, QRS morphology and axis to characterise sinus node function, AV conduction and fascicular block.

  3. 03

    Assessing

    Medication and metabolic review

    Beta-blockers, non-dihydropyridine calcium channel blockers, digoxin, amiodarone, ivabradine, opioids and lithium; plus TFTs, electrolytes and calcium.

  4. 04

    Confirming

    Ambulatory rhythm monitoring

    A 24-hour to 14-day Holter, external event recorder, or an implantable loop recorder for infrequent unexplained syncope.

  5. 05

    Confirming

    Echocardiogram and imaging

    Assessment of structure, LV function and valves; cardiac MRI and selective biopsy where infiltrative or inflammatory disease is suspected.

  6. 06

    Refining

    Provocation and specialist tests

    Exercise testing for chronotropic competence, tilt-table and carotid sinus massage for reflex syncope, and sleep study for suspected OSA.

  7. 07

    Refining

    Serology and genetics where indicated

    Lyme and Chagas serology, autoimmune screen, and genetic testing (SCN5A, LMNA) in familial conduction disease.

Typical timeline: a first ECG to a settled plan in weeks, sooner for high-grade block.

What causes it

Where the slow rate comes from.

A slow rate is a shared endpoint for many different problems, from healthy physiology to conduction system disease and toxicity.

  • Physiological

    Well-conditioned athletes (resting 40 to 50 bpm), sleep, vasovagal responses and healthy young adults with high vagal tone.

  • Sinus bradycardia

    A slow but organised rhythm arising from the sinus node; often benign, occasionally symptomatic.

  • Sick sinus syndrome

    Degenerative disease of the sinus node causing sinus arrest, tachy-brady syndrome and disabling fatigue.

  • AV block

    First (PR >200 ms), Mobitz I (Wenckebach) with progressive PR prolongation, Mobitz II with fixed PR and dropped beats, and third-degree (complete) block.

  • Fascicular and bundle branch block

    Left anterior and posterior fascicular block, LBBB and RBBB; alternating BBB is a pacing indication.

  • Drug-induced

    Beta-blockers, diltiazem and verapamil, digoxin, amiodarone, ivabradine, clonidine, opioids, anticholinesterases and lithium.

  • Electrolyte and metabolic

    Hyperkalaemia, hypothermia, hypothyroidism (myxoedema) and hypocortisolism.

  • Infective myocarditis

    Chagas disease, Lyme carditis, diphtheria and viral myocarditis can all target the conduction system.

  • Infiltrative disease

    Sarcoidosis, amyloidosis, haemochromatosis and cardiac tumours disrupt conduction.

  • Ischaemia

    Inferior MI with AV nodal artery involvement can produce transient block that resolves with revascularisation.

  • Neurological

    Raised intracranial pressure (Cushing reflex), autonomic dysreflexia and high spinal cord injury slow the heart.

  • Congenital and OSA

    Congenital heart block (maternal anti-Ro/La lupus) and obstructive sleep apnoea with morning bradyarrhythmia.

Symptoms

What bradycardia actually feels like.

Many people feel nothing at all. Others notice fatigue, light-headedness or a full collapse. The features below are the ones that matter.

  • Fatigue and low energy

    A persistent drop in stamina, often noticed on stairs or exercise before it is noticed at rest.

  • Light-headedness and presyncope

    Brief spells of feeling faint, greying vision or the world tilting, especially on standing or exertion.

  • Syncope

    A full loss of consciousness with rapid recovery; Stokes-Adams attacks in complete heart block are a red flag.

  • Exercise intolerance

    Breathlessness or exhaustion at low workloads, often reflecting chronotropic incompetence.

  • Confusion and falls

    Especially in older adults, unexplained falls or transient confusion may be the only clue to intermittent bradyarrhythmia.

  • Physiological slow rate

    A resting rate of 40 to 50 bpm in a well-trained athlete, or during sleep, is usually normal and needs no treatment.

  • Asymptomatic finding

    A slow rate discovered on a routine ECG or wearable, with no symptoms, is often benign and just needs context.

  • Red flag - collapse or asystole

    Any syncope with injury, prolonged asystole, or a documented complete heart block needs urgent cardiology review.

Treatment

How bradycardia is treated in the UK.

Reverse what can be reversed, stabilise acute presentations, and pace where the ESC 2021 guidance says the benefit is clear.

  • Treat the underlying cause

    Stop or reduce offending drugs, correct thyroid disease, electrolytes, hypothermia; treat infection, endocarditis or ischaemia.

  • Acute drug reversal

    Atropine 500 mcg to 1 mg IV (up to 3 mg) for symptomatic bradycardia; glucagon, high-dose insulin, calcium and lipid emulsion for beta-blocker or CCB toxicity.

  • Temporary pacing

    Transcutaneous pacing as a bridge, followed by transvenous pacing for unstable bradycardia while the underlying cause is addressed.

  • Permanent pacemaker

    Indicated per ESC 2021 for symptomatic sinus node disease, third-degree block, Mobitz II, alternating BBB and AF with symptomatic bradycardia.

  • Dual-chamber and CRT devices

    DDD dual-chamber pacing preserves AV synchrony; biventricular CRT is added for heart failure with LBBB.

  • Leadless pacemaker

    Micra and similar devices sit inside the right ventricle with no leads and no chest pocket; useful where lead complications must be avoided.

  • Reflex syncope pathway

    Education, hydration, salt and counter-pressure manoeuvres first; pacing reserved for drug-refractory reflex syncope with documented asystole.

  • Device follow-up and DVLA

    Annual device checks with remote monitoring; DVLA advises Group 1 four weeks off driving after pacing and Group 2 six weeks.

What this guide is based on

The sources behind every claim on this page.

UK and European guidance and specialist society standards, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP or cardiologist knows your history and rhythm strips and can tell you which parts apply to you. If in doubt, get seen.

  • European Society of Cardiology. 2021 Guidelines on cardiac pacing and cardiac resynchronization therapy.

  • British Heart Rhythm Society (BHRS). Standards for implantation and follow-up of cardiac rhythm management devices.

  • NICE. Transient loss of consciousness (blackouts) in over-16s (CG109).

  • MHRA and Resuscitation Council UK. Adult bradycardia algorithm and drug guidance.

  • DVLA. Assessing fitness to drive: a guide for medical professionals (2026 update).

Red flags

When bradycardia needs urgent attention.

Most slow-rate findings are manageable. These are the situations that need urgent cardiology, emergency care or admission.

  • Syncope with injury or at the wheel

    Loss of consciousness with trauma or while driving needs urgent cardiology review and DVLA notification.

  • Complete (third-degree) heart block

    No relationship between P waves and QRS complexes on the ECG; permanent pacing is almost always indicated.

  • Mobitz type II AV block

    A fixed PR interval with dropped beats often progresses to complete block; consider pacing even without symptoms.

  • Alternating bundle branch block

    A signal of severe infra-Hisian disease; a permanent pacemaker is usually warranted.

  • Bradycardia on beta-blocker or CCB overdose

    Consider high-dose insulin, glucagon, calcium and lipid emulsion alongside pacing; escalate to critical care early.

  • Hyperkalaemia with wide QRS

    A cardiac emergency; give calcium, insulin-dextrose and consider dialysis while treating the rhythm.

  • Suspected myocarditis or Lyme carditis

    New AV block in a young patient with viral prodrome or tick exposure; admit for monitoring and targeted therapy.

  • Inferior MI with new block

    Right coronary artery involvement can cause transient AV block; usually resolves with revascularisation.

  • Raised intracranial pressure

    The Cushing reflex of bradycardia, hypertension and irregular breathing is a neurosurgical emergency.

Living with it

A slow rate, managed with confidence.

Four things that make the biggest difference day to day: context for the number, a periodic medication review, calm device follow-up and the DVLA rules.

A quiet reminder

A pacemaker is a quiet, capable companion.

Modern devices are small, safe and largely invisible. Most people forget theirs is there within weeks.

  1. 01 Context

    Know what your rate means

    A slow rate is not automatically abnormal; the story your symptoms tell matters far more than the number alone.

  2. 02 Meds

    Review medicines regularly

    Beta-blockers, rate-limiting calcium channel blockers and some eye drops can slow the heart; a periodic review is worth it.

  3. 03 Devices

    Live well with a pacemaker

    Most people return to normal life within weeks; annual checks and remote monitoring keep the device running quietly in the background.

  4. 04 Driving

    Follow the DVLA rules

    Group 1 drivers usually stop for four weeks after pacing and Group 2 for six; syncope has its own rules and needs a clear cardiology plan.

Frequently asked

Everything we get asked about bradycardia.

Quick answers on ECG findings, when a pacemaker is needed, leadless devices and DVLA rules.

  • What counts as bradycardia?

    A resting heart rate below 60 beats per minute. It can be entirely normal in trained athletes and during sleep, or a sign of conduction disease when it causes symptoms or is very slow.

  • Is a slow heart rate always a problem?

    No. Many well-conditioned adults sit in the 40s or low 50s at rest with no symptoms. The clinical question is whether the rate is appropriate for the situation and whether it is causing symptoms.

  • What tests will I need?

    Usually a 12-lead ECG, blood tests including thyroid function and electrolytes, a medication review, and a period of ambulatory monitoring. An echocardiogram is common; an implantable loop recorder is used for infrequent unexplained syncope.

  • When is a pacemaker needed?

    European guidance recommends permanent pacing for symptomatic sinus node disease, third-degree (complete) heart block, symptomatic Mobitz II block, alternating bundle branch block and atrial fibrillation with symptomatic bradycardia, among other indications.

  • What is a leadless pacemaker?

    A small self-contained device implanted directly inside the right ventricle via a vein in the groin, with no leads and no chest pocket. It is a good option where lead complications need to be avoided.

  • When can I drive again after a pacemaker?

    DVLA guidance for Group 1 (car and motorcycle) is a four-week break after implantation. Group 2 (bus and lorry) is six weeks. Syncope has its own rules; your cardiologist can confirm what applies to you.

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