Unstable Bradycardia

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Unstable Bradycardia

Background

·       HR less than 60 BPM

·       Not all bradycardia is bad and scary, some presentations are benign and asymptomatic

·       Broad differential, some examples include:

  • Cardiac (structural/EP): AV block, STEMI, CHD, CM, Aortic dissection, etc.

  • Respiratory: Hypoxia, resp failure

  • Infectious: Myocarditis (viral), Lymes dx, etc.

  • Metabolic/Endocrine: electrolytes, hypothyroidism/myxedema coma, hypoglycemia, hypothermia, heat exhaustion/stroke

  • Tox/iatrogenic: BB, CCB, Dig, Clonidine, Opioids, TCAs, Keppra, Amio, etc.

  • Trauma: increased ICP, spinal injury

·       Place pacer/Zoll pads on patient

·       ACLS guidelines for bradycardia exist

Unstable patient

·       ABCs

·       Don’t let the patient D.I.E

  • Think drugs, ischemia, electrolytes

·       Place on monitor and obtain access

  • If cant get an pIV, then try IO or central line

  • *send for labs, VBG/BMP asap. Looking for electrolyte derangements (hyperK) that can change management

·       Place transcutaneous pacer pads so you’re ready to pace at any moment

  • Anterior/posterior position best

·       Try atropine

  • Doesn’t hurt to try, may work

  • .5mg IV, can be repeated q3min to a max dose of 3mg

·  If atropine is not working, high probability it wont, then start transcutaneous pacing while getting chronotropic medication (pressors) ready and then titrating to desired effect

  • Place dial on pacer mode

  • Set pacer rate >30BPM above pts intrisic rhythm (usually 60-80 BPM)

  • Set mAmp on 40, increase by 5mAmp as needed

  • Monitor for capture

    • Electric capture: downward pacer spike followed by wide QRS

    • Mechanical capture: palpate pulse and correlate with monitor/pulse ox

  • Try to give pt something for pain

  • Get ready to place a TVP

·       Pressors

  • “For symptomatic bradycardia or unstable bradycardia IV infusion a chronotropic agent (dopamine & epinephrine) is now recommended as an equally effective alternative to external pacing when atropine is ineffective.”

    • Thought: takes time to draw up meds/titrate. start external pacing. Get meds ready and administer, especially if hypotensive.

  • Can start either Epinephrine 2-20 micrograms/min or Dopamine 2-20 micrograms/kg/min, titrate accordingly

    • If epi/dopamine don’t work separately, then try them together

      • If bradycardia still not improving, then try isoproterenol 2-10mcg/min

        • Isoproterenol is an analog of epinephrine

·       Additional medications to consider

  • Digoxin  

    • Send dig level

    • Consider digibind

  • CCB

    • Calcium gluconate, high dose insulin

  • BB

    • Glucagon, high dose insuli

  • Organophosphates

    • Atropine, pralidxime

·       STEMI?

  • Usually inferior wall MI

  • Advocate for pt to go to cath lab

 

 

 

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