Bradycardia 🫀
Adult bradycardia management aligned with the RCUK 2021 bradycardia algorithm and eMed.ie: adverse signs, asystole risk, atropine dosing, interim infusions, pacing, and special situations.
Adult bradycardia algorithm
RCUK 2021 bradycardia algorithm: tick findings to see the matching branch. Always follow local resuscitation policy in an emergency.
1. Initial actions
- Assess using the ABCDE approach
- Give oxygen if appropriate and obtain IV access
- Monitor ECG, BP, SpO₂; record 12-lead ECG
- Identify and treat reversible causes (e.g. electrolyte abnormalities)
2. Adverse signs present?
Algorithm branch
Select options aboveComplete the steps above to see the recommended pathway.
Scope
- Use the interactive algorithm at the top to walk through the RCUK 2021 decision tree; the sections below are a full static reference.
- This page summarises the Resuscitation Council UK (RCUK) Adult Bradycardia Algorithm 2021 and the eMed.ie adult bradycardia algorithm for education and quick reference.
- In a real emergency: call for help, request the resuscitation trolley/defibrillator with pacing module, and follow local ALS/resuscitation policy.
- Where RCUK and eMed.ie differ, both are documented — follow your local protocol.
Initial assessment (ABCDE)
- Assess using the ABCDE approach.
- Give oxygen if appropriate and obtain IV access.
- Monitor ECG, BP, SpO₂; record 12-lead ECG.
- Identify and treat reversible causes — e.g. electrolyte abnormalities (hyperkalaemia, hypokalaemia), hypoxia, hypothermia, drugs (β-blockers, calcium channel blockers, digoxin), raised intracranial pressure, myocardial ischaemia/infarction.
- Review medication chart and recent procedures (e.g. spinal anaesthesia).
Adverse signs (life-threatening)
- Per RCUK 2021, assess for evidence of adverse signs:
- 1. Shock
- 2. Syncope
- 3. Myocardial ischaemia
- 4. Heart failure
- If any adverse sign is present → give atropine 500 mcg IV (see Management).
Risk of asystole
- Assess whether the patient is at risk of asystole:
- Recent asystole
- Mobitz II AV block
- Complete heart block with broad QRS
- Ventricular pause > 3 s
- If no adverse signs and no asystole risk → observe and monitor.
- If asystole risk without adverse signs → interim measures and prepare pacing (RCUK algorithm).
Management algorithm (RCUK 2021)
- No adverse signs + no asystole risk → observe; continue monitoring and treat reversible causes.
- Adverse signs present → atropine 500 mcg IV; repeat every 3–5 minutes to a maximum total dose of 3 mg if needed.
- After atropine: if satisfactory response and no asystole risk → observe with monitoring.
- Unsatisfactory response to atropine and/or risk of asystole → interim measures (below) and arrange transvenous pacing; seek expert help.
- Consider pacing in patients who are unstable with symptomatic bradycardia refractory to drug therapy (RCUK ALS guidelines).
- If transcutaneous pacing is ineffective, consider transvenous pacing.
- If atropine is ineffective and transcutaneous pacing is not immediately available, fist pacing can be attempted while waiting for pacing equipment (RCUK ALS guidelines).
- Whenever asystole is diagnosed, check the ECG carefully for P waves — this may respond to pacing unlike true asystole.
Interim measures
- Atropine 500 mcg IV — repeat to maximum total 3 mg (do not give atropine to patients with a cardiac transplant — use aminophylline instead).
- Isoprenaline 5 mcg min⁻¹ IV infusion.
- Adrenaline 2–10 mcg min⁻¹ IV infusion (RCUK).
- Alternative drugs* (see below) OR transcutaneous pacing.
- Seek expert help — arrange transvenous pacing.
Drug doses
- Grouped reference below: interim measures first, then alternative drugs per RCUK 2021.
Bradycardia drug reference
RCUK 2021 interim measures and alternative drugs. Always follow local ALS protocol.
Interim measures
First-line drugs while preparing pacing
Atropine
Interim measure- Dose (RCUK 2021)
- 500 mcg IV bolus; repeat every 3-5 min to max 3 mg
- Notes
- eMed.ie lists 0.5-1 mg IV per dose (500 mcg = 0.5 mg). Avoid in heart transplant
Isoprenaline
Interim measure- Dose (RCUK 2021)
- 5 mcg min⁻¹ IV infusion (starting dose)
- Notes
- Titrate to effect per local protocol
Adrenaline
Interim measure- Dose (RCUK 2021)
- 2-10 mcg min⁻¹ IV infusion
- Notes
- eMed.ie lists 5 mcg min⁻¹ as a starting dose
| Drug | Role | Dose (RCUK 2021) | Notes |
|---|---|---|---|
| Atropine | Interim measure | 500 mcg IV bolus; repeat every 3-5 min to max 3 mg | eMed.ie lists 0.5-1 mg IV per dose (500 mcg = 0.5 mg). Avoid in heart transplant |
| Isoprenaline | Interim measure | 5 mcg min⁻¹ IV infusion (starting dose) | Titrate to effect per local protocol |
| Adrenaline | Interim measure | 2-10 mcg min⁻¹ IV infusion | eMed.ie lists 5 mcg min⁻¹ as a starting dose |
Alternative drugs
If interim measures insufficient (RCUK algorithm footnote*)
Aminophylline
Alternative- Dose (RCUK 2021)
- 100-200 mg slow IV injection
- Notes
- Consider for inferior MI, cardiac transplant, or spinal cord injury (RCUK ALS). eMed: also post-transplant
Dopamine
Alternative- Dose (RCUK 2021)
- 2.5-10 mcg kg⁻¹ min⁻¹ IV infusion
- Notes
- RCUK QRH if pacing unavailable
Glucagon
Alternative- Dose (RCUK 2021)
- 2-10 mg IV, then glucose 5% with 50 mcg kg⁻¹ h⁻¹ IV infusion (RCUK QRH)
- Notes
- RCUK: consider if β-blocker or calcium channel blocker overdose. eMed.ie: no evidence to support glucagon for Ca²⁺ channel or β-blocker overdose; prefer high-dose insulin euglycaemic therapy. Follow local toxicology protocol
Glycopyrrolate
Alternative- Dose (RCUK 2021)
- Can be used instead of atropine
- Notes
- RCUK algorithm footnote
| Drug | Role | Dose (RCUK 2021) | Notes |
|---|---|---|---|
| Aminophylline | Alternative | 100-200 mg slow IV injection | Consider for inferior MI, cardiac transplant, or spinal cord injury (RCUK ALS). eMed: also post-transplant |
| Dopamine | Alternative | 2.5-10 mcg kg⁻¹ min⁻¹ IV infusion | RCUK QRH if pacing unavailable |
| Glucagon | Alternative | 2-10 mg IV, then glucose 5% with 50 mcg kg⁻¹ h⁻¹ IV infusion (RCUK QRH) | RCUK: consider if β-blocker or calcium channel blocker overdose. eMed.ie: no evidence to support glucagon for Ca²⁺ channel or β-blocker overdose; prefer high-dose insulin euglycaemic therapy. Follow local toxicology protocol |
| Glycopyrrolate | Alternative | Can be used instead of atropine | RCUK algorithm footnote |
* Alternatives may also include transcutaneous pacing. See interim measures section above for full pathway.
Special situations
- Cardiac transplant — do not give atropine (can cause high-degree AV block or sinus arrest). Use aminophylline 100–200 mg slow IV instead (RCUK ALS).
- Inferior myocardial infarction — consider aminophylline 100–200 mg slow IV (RCUK ALS; eMed.ie).
- Spinal cord injury — consider aminophylline (RCUK ALS).
- β-blocker or calcium channel blocker overdose — RCUK: consider glucagon. eMed.ie: high-dose insulin euglycaemic therapy; states no evidence to support glucagon — follow local toxicology protocol.
- Digoxin toxicity — call expert help; atropine may be used but specific digoxin toxicity management applies.
- Implanted device — consider antero-posterior pad position for transcutaneous pacing if needed; arrange device interrogation.
Transcutaneous pacing (RCUK QRH)
- Call for help; request defibrillator with pacing module.
- Attach ECG leads and defibrillator pads; consider antero-posterior position if implanted device or trauma.
- Call anaesthetic/ICU for sedation support if pacing required.
- Start pacing and assess response clinically; after electrical capture, set output ~10 mA above capture threshold.
- Check pulse and blood pressure — electrical capture ≠ mechanical capture.
- Call for expert help to assess need for transvenous pacing.
eMed.ie vs RCUK — key differences
- Atropine bolus: RCUK 500 mcg IV; eMed.ie 0.5–1 mg IV (500 mcg falls within eMed range).
- Adrenaline infusion: RCUK 2–10 mcg min⁻¹; eMed.ie 5 mcg min⁻¹ starting dose.
- Overdose (β-blocker / CCB): RCUK lists glucagon; eMed.ie recommends high-dose insulin euglycaemic therapy and states no evidence for glucagon.
- Both sources agree on isoprenaline 5 mcg min⁻¹, aminophylline for AMI/transplant, max atropine 3 mg, and transcutaneous/transvenous pacing pathway.
Actions for interns
- Recognise adverse signs and risk-of-asystole features on ECG/monitoring.
- Call for senior help and resuscitation support early if unstable or pacing may be needed.
- Give atropine 500 mcg IV if adverse signs — document time, dose, and response.
- Prepare for transcutaneous pacing: defibrillator, pads, sedation support.
- Send urgent bloods (electrolytes, Mg²⁺, troponin if ischaemia suspected), 12-lead ECG, and document rhythm.
- Escalate to cardiology/ICU for transvenous pacing if not responding to first-line measures.
Note Template
Ready-to-use clinical note structure
🕒 13 / 10 / 2026 — 20:07 ATRP re: bradycardia Patient: [age] [sex] Admission Dx: [reason for admission] PMHx: [IHD, heart failure, cardiac transplant, PPM/ICD, structural heart disease] 🧾 Hx: • Symptoms: [syncope / pre-syncope / dizziness / chest pain / SOB / none] • Onset: [acute / gradual] • Triggers: [medication change / recent MI / spinal anaesthesia / other] • Meds: [β-blockers / CCBs / digoxin / amiodarone / clonidine / other] 🩺 Exam: • HR: __ BP: __ RR: __ Temp: __ SpO₂: __ • Perfusion: [shock / warm / cool peripheries] • Heart sounds: [normal / murmur / cannon a-waves] • Lungs: [clear / pulmonary oedema] • Neuro: [GCS __ / syncope witnessed] 🧪 Investigations: • 12-lead ECG: [sinus bradycardia / Mobitz I / Mobitz II / complete heart block / junctional / other] • Adverse signs: [shock / syncope / myocardial ischaemia / heart failure / none] • Asystole risk: [recent asystole / Mobitz II / CHB broad QRS / pause >3s / none] • Bloods: K __ Mg __ troponin [ ] digoxin level [ ] 💊 Management (RCUK 2021): • Atropine given: [yes/no] — dose __ time __ response [satisfactory / unsatisfactory] • Infusions: [isoprenaline / adrenaline / dopamine / none] • Pacing: [transcutaneous / transvenous / none / planned] • Reversible causes treated: [electrolytes / hypoxia / drug hold / other] 📋 Impression: Rhythm: [describe] Haemodynamic status: [stable / unstable] Likely cause: [medication / ischaemia / conduction disease / electrolyte / toxicology / other] 📌 Plan: • Continue monitoring on [telemetry / CCU / ward] • Cardiology / ICU input: [yes/no] • Repeat ECG / labs: [timing] • Medication changes: [hold β-blocker/CCB / other] 👤 [Your Name], [Role] IMC: _______
Educational reference only. Medical disclaimer