Bradycardia is generally defined as a heart rate of < 60/min. All patients require urgent evaluation with ECG and monitoring. Patients with unstable bradycardia require immediate stabilization, initially with IV atropine, followed by transcutaneous pacing and/or IV chronotropic medications (e.g., dopamine, epinephrine), and transvenous pacing for refractory bradycardia. Treatment should also address reversible underlying , e.g., hypoxemia, acute coronary syndrome, electrolyte disturbances, and medication-induced bradycardia. Stable patients may not require immediate intervention, but often require monitoring and investigations to determine the underlying etiology and risk of progression to unstable bradycardia or sudden cardiac death. Definitive management depends on the underlying and can include permanent pacemaker implantation for patients with nonreversible bradyarrhythmias.
- Follow pulse. and check
- present: Follow .
- Stable bradycardia: Manage according to underlying etiology and symptom severity.
Patients or only mildly typically do not require acute intervention. 
Initial management of bradycardia
- Call for help.
- Establish IV access.
- Bring crash cart to bedside and attach pads.
- Begin continuous cardiac and respiratory monitoring.
- Unstable bradycardia: Begin stabilization according to the .
- Evaluate underlying rhythm.
- Identify and treat reversible supplemental O2 for hypoxemia.  , e.g.,
- Consult cardiology.
Overview of bradyarrhythmias
|Overview of common bradyarrhythmias by ECG findings|
Clinical features of unstable bradycardia 
- Acute altered mental status
- Ischemic chest pain
- Acute heart failure
- airway and breathing despite adequate
Adult unstable bradycardia algorithm 
Startand simultaneously with the following treatment:
- First-line: IV atropine
- If refractory to atropine: Start temporizing measures.
- If refractory to pharmacotherapy: Consult cardiology for .
Special situations 
- No IV access or IO access: Consider transcutaneous pacing as first-line intervention while awaiting vascular access. 
- Acute coronary syndrome
- Recent heart transplant
- Known infranodal block or a wide QRS with AV block: Consider transcutaneous pacing as first-line intervention instead of atropine. 
Spinal cord injury: Consider alternative chronotropic medications if unresponsive to atropine and inotropes.
- Aminophylline 
- OR Theophylline 
- Begin definitive therapy for specific bradyarrhythmias under specialist guidance.
- See “ .”
- See “ .”
- Identify .
- Continue treatment of the underlying .
- ABCDE survey
- IV access, continuous telemetry, and pulse oximetry
- Unstable and/or symptomatic bradycardia: Administer atropine.
- If atropine is ineffective, consider temporizing measures (tailored to the patient).
- Consult cardiology.
- Consider transvenous pacing.
- Identify and treat the underlying .
- Admit to the ICU.
Provideconcurrently for all patients.
If develop at any time, follow the .
- Conduct comprehensive clinical evaluation and obtain 12-lead ECG in all patients.
- Consider additional diagnostics on an individual basis under specialist guidance.
- Asymptomatic or only mildly symptomatic patients typically do not require acute intervention.
- Definitive management depends on the underlying rhythm.
is an .
Consult cardiology as disposition varies depending on underlying rhythm and etiology, symptom severity, and patient factors.
Transcutaneous pacing 
- Definition: a temporizing treatment for bradyarrhythmias in which electrical impulses are delivered through pacing pads placed on the chest wall to stimulate cardiac contraction
- Indication: unstable bradycardia for which pharmacotherapy alone either is ineffective, not readily available, or contraindicated
- Contraindications: no absolute contraindications
- Pacemaker spike: A narrow upward deflection on an ECG tracing caused by an electrical impulse from a pacemaker.
- Electrical capture
- Mechanical capture
- Pacer pads
- Transcutaneous pacemaker
- Continuous cardiac monitoring
- Pulse oximetry
- Bedside ultrasound (optional)
Landmarks and positioning
- Anterior-lateral pacer pad placement
- Anterior-posterior pacer pad placement
Consider placing pacer pads early in patients with bradyarrhythmias at risk of decompensation. 
- Apply pacer pads to the chest.
- Connect the cable from the pads to the pacemaker.
- Turn on the pacemaker and select the pacer function.
- Verify that the pacemaker detects the patient's intrinsic rhythm.
- Set the pacing rate higher than the patient's native heart rate (generally 60–70/minute).
- Increase the current output until occurs. 
- Confirm POCUS. clinically or using
- Maintain the current 5–10 mA above the minimum current required for mechanical capture. 
- Provide hemodynamic instability. for conscious patients, unless there is persistent
In the unconscious or near-arrest patient, start the current at maximum and decrease until capture is lost. Maintain the final output at 5–10 mA above this threshold. 
Postprocedural care 
- Optimize etomidate, ketamine).  , preferably with hemodynamically neutral (e.g.,
- Consult cardiology for definitive management.
Consider the following ifor is lost:
- Reposition pacer pads.
- Improve skin-pad contact.
- Minimize chest impedance.
- Manage systemic conditions (e.g., myocardial ischemia, acidosis, hypoxia).
- Skin burns
- Loss of and/or
- Tachyarrhythmias (e.g., ventricular fibrillation)
- Cough and/or hiccups
Transvenous pacing 
- Definition: The delivery of electrical impulses to stimulate cardiac contraction using an electrode placed via a central venous access site into the right ventricle; often used as a bridge to permanent pacemaker implantation
- Indications 
- Contraindications: prosthetic tricuspid valve, severe hypothermia
- Complications: Usually related to vascular access (see “Complications” in “Central venous access.”)
Acute management of reversible causes 
- Provide and/or for .
- Identify and .
- Check core temperature and provide hypothermia. for
- Identify and treat if needed.
- Screen for and treat .
- Obtain laboratory studies for metabolic causes (e.g., electrolytes, TSH) and treat urgent disturbances.
- See “ .”
- See “ .”
- Treat , if present.
Medication-induced bradycardia 
Management depends on the indication and individual patient risk. Consult the prescribing clinician if available.
- Noncritical medication: Consider temporary hold or permanent discontinuation.
- Critical medication: Consider dosage reduction or alternative agents under specialist guidance.
- Follow the .
- If indicated, consider adding antidotes for (e.g., , , ), such as:
Etiologies by underlying mechanism
Increased vagal tone
|Degeneration of the conducting system|