ACLS: Bradycardia
Background
- Only intervene if pt is symptomatic (hypotension, AMS, chest pain, pulm edema)
Categories
- Sinus node dysfunction
- Sinus bradycardia
- Sinus arrest
- Tachy-brady syndrome (sick sinus)
- Chronotropic incompetence
- AV node dysfunction
- 1st degree AV block
- 2nd degree AV block Mobitz I/Wenckebach
- 2nd degree AV block Mobitz II
- 3rd degree AV block (complete heart block)
Differential
- Ischemia/Infarction
- Inferior MI (involving RCA)
- Neurocardiogenic/reflex-mediated
- Increased ICP
- Vasovagal reflex
- Hypersensitive carotid sinus syndrome
- Intra-abdominal hemorrhage (i.e. ruptured ectopic)
- Metabolic/endocrine/environmental
- Hyperkalemia
- Hypothermia (Osborn waves on ECG)
- Hypothyrodism
- Toxicologic
- B-blocker
- Ca-channel blocker
- Digoxin toxicity
- Opioids
- Organophosphates
- Infectious/Postinfectious
- Chagas dz
- Lyme dz
- Syphilis
Sick Sinus Syndrome
- Collection of bradyarrhythmias with or without tachycardia[1]
- 50% have alternating bradycardia and tachycardia
- Causes include:
- Intrinsic: degenerative fibrosis, infiltrative disease process, ion channel dysfunction, SA node remodeling
- Extrinsic: pharmacologic, metabolic/electrolyte disturbance, autonomic, OSA
- Clinical manifestations related to end-organ hypoperfusion
- Syncope/pre-syncope (50%)
- Dx - ECG identification, inpatient telemetry, outpatient Holter monitoring, event monitoring, loop monitoring
- ECG
- Tx - remove extrinsic factors and/or pacemakers
- Pacemakers do not reduce mortality, only decrease symptoms
- Complications
- (50%) Tachy-brady syndrome with atrial fibrillation or atrial flutter
- (50%) AV block
Treatment
- Atropine
- Can be used as temporizing measure (while awaiting pacing and/or chronotropes)
- Use cautiously in pts w/ ongoing ischemia (tachycardia may worsen ischemia)
- 0.5mg q3-5min (max 3 mg or 6 doses)
- may not work in 2nd/3rd deg HB, heart transplant
- Chronotropes
- Dopamine 2-10mcg/kg/min
- Epinephrine 2-10mcg/min
- Transcutaneous Pacing
- Transvenous Pacing
Antidotes for toxicologic causes
- Beta-Blocker Toxicity
- glucagon 5mg IV Q10min (rpt up to 3 doses)
- Calcium Channel Blocker Toxicity
- Calcium gluconate 3g OR insulin 1U/kg bolus
- Digoxin Toxicity
- Dig immune Fab 10-20 vials
- Opioid Toxicity
- Nalaxone 0.4mg IV
- Organophosphate Toxicity
- Atropine 2mg IV OR Pralidoxime 2g IV over 10-15min
- Beta-Blocker Toxicity
See Also
- ↑ Semelka, M et Al. Sick Sinus Syndrome: A Review. Am Fam Physician. 2013 May 15;87(10):691-696. http://www.aafp.org/afp/2013/0515/p691.html