Arrythmias (simple summary)

TOO  FAST				TOO  SLOW
NARROW COMPLEX		BROAD COMPLEX		NARROW COMPLEX		BROAD COMPLEX
REGUALR	IRREGULAR	REGULAR	IRREGULAR
SVT Flutter Sinus Tachy	AF A-flutter with variable block	VT Conduction abN	VF AF with LBBB	Sinus (medications) AF (medications) SSS(sick sinus Syndrome) 2nd degree heart block		BBB 3rd degree HB Poisoned Heart (hypoxia, acidosis, overdose, hypothermia)
TOO  FAST				TOO  SLOW
Compromised		Stable		Compromised	Stable
Electricity		Medical Management		= treat rhythm Atropine Adrenaline Pacemaker	= treat cause Ischaemia Medications SSS ABG, K+
Check K+, Mg, Digoxin toxicity, B-Blocker, Systemic illness

Management of Cardiac Arrest and Arrhythmias

Resuscitation Drugs

Shockable VT/VF:

• Adrenaline: 1 mg every 3-5 minutes

Non-Shockable Asystole/PEA:

• Adrenaline: 1 mg every 3-5 minutes (every 2nd loop)

Ventricular Tachycardia (GCS 15):

• Amiodarone:
  • 300 mg + 250 mL 5% glucose over 30 minutes
  • Then 900 mg + 500 mL 5% glucose over 23 hours (administer as two 11.5-hour infusions)
• Lignocaine: 1 mg/kg if no amiodarone available (no significant benefit)

Torsades de Pointes, Digoxin Toxicity, Hypokalemia:

• Magnesium Sulfate (MgSO4):
  • 1-2 g over 10 minutes: For cardiac arrhythmia, torsades, seizures
  • 1 g in 100 mL Normal Saline over 30 minutes: For slow replacement
• Calcium Gluconate: 1 g to replenish calcium (often administered together with magnesium)

Magnesium Overdose (during pre-eclampsia treatment):

• Dialysis is the treatment of choice.
• Calcium Chloride 10% (5-10 mL) as an alternative treatment.

Supraventricular Tachycardia (SVT):

• Adenosine:
  • 3 mg → 6 mg → 12 mg (adult)
  • 0.04 to 0.25 mg/kg (children)
  • Note: May cause pain, anxiety, sense of doom
  • Contraindications: Sick sinus syndrome, symptomatic bradycardia, second and third degree AV block, allergy, caution with asthma and COPD

Management of Bradycardia

Presence of Adverse Signs:

• Systolic BP <90 mmHg
• HR <40 per minute
• Heart failure
• Ventricular arrhythmias requiring suppression

Risk of Asystole:

• Recent episode of asystole
• Ventricular pauses >3 seconds
• Mobitz type 2 – 2nd Degree heart block
• 3rd Degree heart block with broadened QRS complexes

Immediate Management:

1. Initial Steps for All Patients:
   • Provide high-flow oxygen.
   • Establish IV access.
2. If Adverse Signs are Present:
   • Atropine: 500 mcg-1 mg IV every 5 minutes
     • Doses <500 mcg may slow HR; not recommended for PEA/asystole
     • If inadequate response, repeat Atropine 0.5 mg up to a maximum of 3 mg.
   • If response is still inadequate:
     • Arrange external transcutaneous pacing.
     • If unavailable, start:
       • Isoprenaline:
         • 10-20 mcg IV bolus, followed by an infusion at 1-4 mcg/min.
       • Adrenaline:
         • IV Bolus: Dilute 50-200 mcg in 10 mL of normal saline or 5% dextrose.
         • IV Infusion: Dilute 1 mg in 100 mL of normal saline or 5% dextrose, start at 3 mL/hr, titrate according to response.
3. If No Adverse Signs are Present:
   • Determine the risk of asystole.
   • If no risk, observe the patient.
   • If risk is present, consider interim measures such as Atropine, Epinephrine, and transcutaneous pacing.
   • Obtain expert help and arrange transvenous pacing.

Special Considerations for AV Block Complicating Acute Myocardial Infarction:

• Inferior MI:
  • AV block is usually at the AV node and transient.
  • Atropine may be required.
• Anterior MI:
  • AV block is at the distal conducting tissues in the ventricle, likely permanent.
  • Associated with hemodynamic compromise.
  • Emergency temporary pacing usually required.

Symptomatic Bradycardia:

• Atropine: 500 mcg-1 mg IV every 5 minutes (maximum 3 mg)
  • Doses <500 mcg may slow HR; not recommended for PEA/asystole

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