Fatal Bradycardia: Immediate Emergency Management
For an adult patient with fatal bradycardia (pulseless or peri-arrest), immediately initiate CPR and follow the cardiac arrest algorithm—atropine and other bradycardia medications are NOT indicated in pulseless arrest. 1
Critical Initial Decision Point: Pulse Present or Absent?
If NO pulse is detected:
- Begin high-quality CPR immediately at a rate of at least 100 compressions per minute 1
- Follow the ACLS Pulseless Arrest Algorithm (asystole/PEA pathway) 1
- Administer epinephrine 1 mg IV every 3-5 minutes during resuscitation 1
- Do NOT give atropine—it has been removed from cardiac arrest algorithms due to lack of efficacy 1
- Search for and treat reversible causes (H's and T's) 1
If pulse IS present but patient is profoundly unstable (imminent arrest):
Management Algorithm for Symptomatic Bradycardia With Pulse
Step 1: Immediate Stabilization (First 60 Seconds)
- Maintain patent airway and assist breathing as necessary 1, 2
- Provide supplemental oxygen if hypoxemic or showing increased work of breathing 1
- Attach cardiac monitor to identify rhythm and monitor blood pressure/oximetry 1, 2
- Establish IV access immediately 1, 2
- Obtain 12-lead ECG if available, but do not delay treatment 1, 2
Step 2: Assess Severity (Heart Rate and Symptoms)
Fatal/life-threatening bradycardia is defined by:
- Heart rate typically <50 bpm (often <40 bpm in critical cases) 1, 2
- PLUS signs of severe hemodynamic compromise:
Step 3: First-Line Pharmacologic Treatment
Atropine 0.5-1 mg IV push 1, 2
- Repeat every 3-5 minutes as needed 1, 2
- Maximum total dose: 3 mg 1, 2
- Critical warning: Doses <0.5 mg may paradoxically worsen bradycardia—avoid 1, 2
Atropine is likely to FAIL in these rhythms (prepare for pacing immediately):
- Type II second-degree AV block 1, 2
- Third-degree AV block with wide QRS complex 1, 2
- New bundle branch block in setting of acute MI 1, 2
- Heart transplant patients (may cause paradoxical high-grade AV block) 1, 2
Step 4: Second-Line Treatment (If Atropine Fails or While Preparing for Pacing)
Choose ONE of the following chronotropic infusions:
Dopamine 5-10 mcg/kg/min IV infusion (preferred for most situations) 1, 2
- Start at 5 mcg/kg/min and titrate up by 5 mcg/kg/min every 2 minutes 2
- Maximum dose: 20 mcg/kg/min (higher doses cause excessive vasoconstriction and arrhythmias) 2
- Provides both chronotropic and inotropic effects 2
OR
Epinephrine 2-10 mcg/min IV infusion (preferred if severe hypotension with shock) 1, 2
- Provides stronger chronotropic and inotropic support than dopamine 2
- More profound vasoconstriction—use when BP critically low 2
- Mandatory in heart transplant patients (atropine contraindicated) 2
Alternative (less commonly used):
- Isoproterenol 2-10 mcg/min IV infusion 2
Step 5: Transcutaneous Pacing (TCP)
Initiate TCP immediately if: 1, 2
- Patient remains unstable despite atropine (Class IIa recommendation) 1, 2
- Type II second-degree or third-degree AV block with wide QRS 1, 2
- Atropine is contraindicated or predicted to fail 2
TCP technique:
- Apply pacing pads without delay 2
- Start at 60-80 bpm 2
- Increase output until electrical and mechanical capture achieved 2
- Provide sedation/analgesia if patient conscious (TCP is painful) 2
- TCP is a temporizing measure only—prepare for transvenous pacing 1, 2
Step 6: Definitive Management
- Indicated when TCP fails or prolonged pacing anticipated 1, 2
- Consult cardiology/electrophysiology immediately 1
Permanent pacemaker implantation 2
- Required when symptomatic bradycardia persists after reversible causes excluded 2
- Indicated for high-grade AV block, symptomatic sinus node dysfunction, or bifascicular block with intermittent complete heart block 2
Special Clinical Scenarios and Critical Warnings
Acute Coronary Syndrome/Myocardial Infarction
Use atropine with extreme caution: 2
- Increasing heart rate may worsen ischemia or increase infarct size 1, 2
- Limit total atropine dose to 0.03-0.04 mg/kg in patients with known CAD 2
- Inferior MI with nodal-level bradycardia: Atropine usually effective 2
- Anterior MI with new BBB or Type II/III AV block: Atropine contraindicated—proceed directly to pacing 2
Drug-Induced Bradycardia
Identify and discontinue offending agents: 2
- Beta-blockers 2
- Calcium channel blockers (diltiazem, verapamil) 2
- Digoxin 2
- Amiodarone 2
- Atypical antipsychotics (e.g., quetiapine) 2
Neurogenic Shock/Spinal Cord Injury
- Atropine often fails in this population 2
- Consider aminophylline 6 mg/kg IV over 20-30 minutes as alternative 2
- Early vasopressor support (dopamine or epinephrine) typically required 2
Common Pitfalls to Avoid
Do not give atropine in pulseless cardiac arrest—it is ineffective and delays CPR 1
Do not delay TCP while giving multiple atropine doses in unstable patients—apply pacing pads early and pace if no response to first atropine dose 1, 2
Do not use atropine for Type II second-degree or third-degree AV block with wide QRS—it will not work and may worsen the block 1, 2
Do not treat asymptomatic bradycardia—even rates <40 bpm require no treatment if patient is stable and asymptomatic 1, 2
Do not exceed dopamine 20 mcg/kg/min—higher doses cause dangerous vasoconstriction and arrhythmias 2
Do not use verapamil or diltiazem for bradycardia—these are AV nodal blockers and will worsen the condition 1
Monitoring During Resuscitation
- Continuous cardiac monitoring and pulse checks 1, 2
- Blood pressure every 2-5 minutes 2
- Reassess rhythm and hemodynamic status after each intervention 1, 2
- Monitor for complications: excessive tachycardia, ventricular arrhythmias, worsening ischemia 2
Prognosis
- Mortality for compromising bradycardia requiring emergency intervention is approximately 5% at 30 days 3
- About 20% of patients with compromising bradycardia require temporary emergency pacing for initial stabilization 3
- Approximately 50% ultimately require permanent pacemaker implantation 3
- Patients who achieve normal sinus rhythm are likely to do so during the initial prehospital/ED interval 4