Makindo Medical Notes

Related Subjects: |Adrenaline/Epinephrine |Atropine |Adult Resus:Acute Anaphylaxis |Adult Resus:Basic Life Support |Adult Resus: Advanced Life Support |Adult Resus: Obstetric Cardiac Arrest |Newborn/Child Resus: All |Acute Hypotension |Cardiogenic shock |Distributive Shock |Hypovolaemic or Haemorrhagic Shock |Obstructive Shock |Septic Shock and Sepsis |Shock (General Assessment) |Toxic Shock Syndrome |Resus:Bradycardia |Resus:Tachycardia |Resus:Hyperkalaemia |Resus:Post Resuscitation Algorithm |Resus:Acute Severe Asthma |Resus:Acute Haemorrhage

See topic on Transcutaneous and Transvenous pacing

Bradycardia

>Bradycardia

About

• Always get a 12 lead ECG
• Acute MI/Ageing conduction tissue/Endocarditis
• Some may be caused by acute MI
• may be due to rate slowing drugs

Caused by problems at different levels

• Sinus node: sick sinus syndrome, hypothyroid
• AV node: complete heart block, slow AF
• His–Purkinje system: bifascicular block (left axis deviation and RBBB).
• Stop Drugs - beta blockers, Digoxin, Verapamil and other CCB
• Bradycardia and mild heart block normal in athletes who are usually asymptomatic
• Bradycardia and transient conduction disturbance (1 HB and Mobitz type I or Wenckebach) are seen in healthy people during sleep. Great caution is needed when interpreting rhythm disturbances at night. Clinical correlation.
• Acute MI
  • RCA to AV nodal artery causing CHB may reverse with reperfusion
  • LAD disease with large infarct causing CHB or LBBB
• Pacemaker failure: take dizzy spells in a patient with a pacemaker seriously. Look at ECG to see if PPM is working. Pacing clinic check are required

Investigations

• FBC, Electrolytes (particularly potassium), TFTs
• Cardiac biochemical markers e.g. Troponin
• Chest X ray at heart size and for evidence of pulmonary oedema
• 24 h ECG monitor (if symptoms intermittent and 12-lead ECG not diagnostic)
• Echocardiography (if clinical suspicion that heart is structurally abnormal)

High Risk of asystole

• Recent asystole
• Mobitz II AV Block
• Complete heart block with Broad QRS
• Ventricular pause > 3 secs

Management

• If significant move to CCU.
• Atropine 500 mcg (0.5 mg) IV stat repeated up to 3 mg
• Transcutaneous pacing
• Isoprenaline infusion can be tried 5 mcg/min IV
• Adrenaline (Epinephrine) 2-10 mcg/min
• Dopamine 2 to 10 mcg/kg per minute
• Consider glucagon 50-150 mcg/kg IV in 5% glucose in cases of beta-blocker overdose, with precautions to protect the airway in case of vomiting
• Ultimately failure of medical treatment requires transvenous pacing if the patient remains compromised.

Temporary Pacing Indications

• Acute MI and CHB. May resolve after reperfusion if RCA.
• Acute MI and Wenckebach: atropine in an inferior MI; pace if anterior MI
• Bundle branch block: Pace prophylactically if trifascicular disease
• Sino-atrial disease + serious symptoms: Pace unless responds to atropine.
• Pre-op: surgery required with Type 2/CHB. liaise with the anaesthetist.
• Drug poisoning, eg with Beta blockers, digoxin, or verapamil.
• Symptomatic bradycardia, uncontrolled by atropine or isoprenaline.
• Suppression of drug-resistant VT and SVT (overdrive pacing; do on ICU).
• Asystolic cardiac arrest with P-wave activity (ventricular standstill).
• During or after cardiac surgery.eg around the AV node or bundle of His