Bradycardia

A quick overview of the classification, diagnosis and management of the most important bradycardias.

 

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Video Duration: 10 minutes

  • Bradycardia
    Created by Adam Douglas
    General
    Epidemiology

    HR < 60 bpm. May be physiological in athletes/sleep, or pathological

    Pathology
    Failure of SAN or conduction system
    • 1st: PR interval >0.2 s;
    • 2nd: Mobitz I: gradually lengthening PR interval until dropped QRS, then reset; Mobitz II: variable conduction of impulses through AVN (2 or 3 P waves to QRS)
    • 3rd: Complete HB, complete dissociation between P waves and QRS complex
    Top three causes

    Cardiac: ischaemic (SAN, AVN), fibrosis (nodal tissue, elderly)

    Iatrogenic: B-blockers, digoxin

    Metabolic: hypothyroid, hypothermia

    Clinical Features
    Symptoms

    Asymptomatic

    Stokes-Adams drop attacks (sudden LOC, pallor then flushing)

    Palpitations, dizziness

    Signs

    Low pulse (<60 bpm)

    Investigations
    Cultures

    None

    Bloods

    None

    Imaging

    None

    Scopic/Biopsy

    None

    Functional

    None

    Treatment
    Conservative

    ALS algorithm. Adverse features present? Risk of asystole?

    Medical

    Atropine 0.5 mg IV (max 3 mg in acute)

    Surgical

    Definitive pacemaker