Acute Care

ACLS: Bradycardia Management Algorithm

See flow chart (View image)

Bradycardia

1. Definition
   • Defined as a HR < 60 bpm
   • Symptomatic bradycardia usually manifests when heart rate falls below 50 bpm
   • ACLS guidelines
     • Clinicians not to intervene unless patient exhibits signs/symptoms of inadequate tissue perfusion secondary to bradycardia

First Steps: Identify and Treat Underlying Cause(s)

1. Maintain patent airway
   • Non-invasive airway maneuvers
2. Assist breathing as needed
3. Oxygen if hypoxemic
4. Cardiac monitor
   • ECG (identify rhythm) (View image)
     • 12-lead if available (DO NOT delay Therapy)
   • Blood pressure
   • Oximetry
5. Establish IV access
6. Treat underlying cause

Bradyarrhythmia Symptoms Present?

1. Persistent bradyarrhythmia signs/symptoms
   • Altered mental status (acute)
   • Ischemic chest discomfort
   • Hypotension
   • Acute heart failure
   • Acute pulmonary edema
   • Other signs of shock
     • Cool, clammy skin
     • Pale or ashen skin
     • Rapid pulse
     • Rapid breathing
     • Nausea or vomiting
     • Mydriasis
     • Weakness or fatigue
     • Dizziness or fainting
2. Signs/symptoms of inadequate tissue perfusion?
   • NO
     • Monitor and observe
   • YES
     • Treat as symptomatic bradycardia

If Poor Perfusion

1. Pharmacologic agents
   • Atropine
     • First dose: 0.5 mg IV; repeat q3-5min
     • Maximum dosage: 3mg
     • Administer while preparing for prompt temporary cardiac pacing
       • Transvenous cardiac pacing method preferred
       • Transcutaneous method second option
       • Require cardiology consultation, and admission for evaluation for possible permanent pacemaker placement
     • If atropine is ineffective, begin pacing and add chronotropic agents in severe symptomatic cases
     • Precautions
       • Acute coronary ischemia/MI (may worsen ischemia or increase zone of infarction)
       • DO NOT give to pts with cardiac transplants (denervated)
       • Doses < 0.5 mg may cause paradoxical HR slowing
   • Consider 2nd line drugs (while waiting for pacer OR if pacer ineffective)
     • Dopamine: 2-20 mcg/kg/min
       • Titrate to patient response
       • Taper slowly
     • Epinephrine: 2-10 mcg/min
       • Titrate to patient response
2. Pacers
   • Transcutaneous pacing (use without delay in high-grade block)
     • 2° Type II block (View image)
     • 3° block (View image)
     • Sedation & analgesia as needed (monitor closely)
   • Transvenous pacing (expert consultation may be required)
     • Documented recent asystole (> 3 sec ventricular standstill)
     • 2° Mobitz type II AV block
     • 3° complete AV block (esp. broad QRS or initial HR < 40 bpm)
3. Treat contributing causes

Observe/Monitor

1. If Pulseless Arrest Develops
   • See Pulseless Arrest Algorithm

Search for/treat possible contributing causes

1. The 6 Hs
   • Hypovolemia
     • Infusion of normal saline or Ringer’s lactate
   • Hypoxia
     • Airway management and effective oxygenation
   • Hydrogen ion (acidosis)
     • Hyperventilation; consider sodium bicarbonate bolus
   • Hypo/Hyperkalemia
     • Hypokalemia:
       • Address underlying cause
       • Potassium replenishment without dextrose
       • IV Magnesium infusion
     • Hyperkalemia:
       • Address underlying cause
       • Consider
         • Calcium chloride/gluconate
         • Sodium bicarbonate
         • Insulin and glucose protocol
         • Beta agonists
         • Sodium polystyrene sulfonate
         • Dialysis
   • Hypoglycemia
     • IV bolus of dextrose
   • Hypothermia
     • Gradual rewarming
2. The 5 Ts
   • Toxins
     • Based on the specific toxin
   • Tamponade (cardiac)
     • Pericardiocentesis
   • Tension pneumothorax
     • Thoracostomy or needle decompression
   • Thrombosis (coronary, pulmonary)
     • Surgical embolectomy; administration of fibrinolytics; CABG
   • Trauma (hypovolemia, increased ICP)
     • Maintain ABC; attend to underlying lesions
3. Also consider these specific etiologies:
   • High-vagal tone
     • Myocardial infarction
     • Exaggerated vagal activity
   • Medication-induced
     • Sympatholytic drugs: beta-blockers, methyldopa, clonidine
     • Parasympathomimetic agents: acetylcholine, carbachol, acetylcholinesterase inhibitors
     • Non-dihydropyridine calcium channel blockers: diltiazem and verapamil
     • Digitalis
     • Opioids and sedatives
     • Antiarrhythmic drugs
     • Lithium
     • Organophosphate compounds
     • Chemotherapeutic agents: paclitaxel, thalidomide
   • High-degree AV block with narrow QRS complex (thought to originate at or above the AV node)
   • Other causes
     • Obstructive sleep apnea
     • Nervous system lesions/ raised intracranial pressure
     • Hypothyroidism
     • Anorexia nervosa
     • Hypothermia
     • Prolonged hypoxia
     • Infections:
       • Lyme disease
       • Chagas disease
       • Legionella
       • Q fever
       • Typhoid fever
       • Babesiosis
       • Malaria
       • Dengue fever
       • Rocky Mountain Spotted fever
       • Viral hemorrhagic fevers: Ebola

Reference

1. Panchal AR, Bartos JA, Cabanas JG, et al. Part 3: Adult Basic and Advanced Life Support: 2020 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. Oct 21, 2020;142:S366-S468
2. https://www.ncbi.nlm.nih.gov/books/NBK493201/
3. Cleveland clinic. Bradycardia. Available at: https://my.clevelandclinic.org/health/diseases/17841-bradycardia. [Accessed March 2022]
4. ACLS medical training. ACLS Bradycardia Algorithm. Available at: https://www.aclsmedicaltraining.com/adult-bradycardia-algorithm/. [Accessed March 2022]

Contributor(s)

1. Beverage, Jennifer E., DO
2. Courtney, Whitney, DO
3. Ho, Nghia, MD
4. Cherian, Geo, MD

Updated/Reviewed: March 2022