Lecture Notes on Arrhythmia

Introduction

• Presenter: Tom from Zero to Finals.
• Topic: Arrhythmia.
• Resources: Written notes, flashcards, and questions available at Zero to Finals website.
• Guidelines: Based on the Resuscitation Council UK 2021 guidelines.

Arrhythmia Overview

• Arrhythmias are abnormal heart rhythms due to interruption in electrical signals.
• Several types with different causes and management options.

Cardiac Arrest Rhythms

• Shockable Rhythms:
  • Ventricular Tachycardia.
  • Ventricular Fibrillation.
• Non-Shockable Rhythms:
  • Asystole.
  • Pulseless Electrical Activity.

Narrow Complex Tachycardia

• Fast heart rate with QRS < 0.12 seconds.
• Differentials:
  • Sinus Tachycardia: Treat underlying cause.
  • Supraventricular Tachycardia: Treat with vagal maneuvers and adenosine.
  • Atrial Fibrillation & Flutter: Rate or rhythm control.
• Life-threatening Features: Treat with synchronized DC cardioversion; add intravenous amiodarone if needed.

Broad Complex Tachycardia

• Fast heart rate with QRS > 0.12 seconds.
• Types:
  • Ventricular Tachycardia or unknown cause: IV amiodarone.
  • Polymorphic Ventricular Tachycardia: IV magnesium.
  • Atrial Fibrillation with bundle branch block: Treat as atrial fibrillation.
  • Supraventricular Tachycardia with bundle branch block: Treat as supraventricular tachycardia.
• Life-threatening Features: Similar treatment as narrow complex tachycardia.

Atrial Flutter

• Cause: Re-entrant rhythm in the atrium.
• ECG Appearance: Sawtooth pattern.
• Treatment: Similar to atrial fibrillation; consider radiofrequency ablation.

Prolonged QT Interval

• Definition: QT interval > 440ms in men, > 460ms in women.
• Causes: Inherited conditions, medications, electrolyte imbalances.
• Management: Avoid QT prolonging medications, correct electrolyte disturbances, use beta blockers.
• Acute Management of Torsades de Pointes: Correct underlying causes, magnesium infusion, defibrillation.

Ventricular Ectopics

• Presentation: Random extra or missed beats.
• ECG: Isolated broad QRS complexes.
• Management: Reassurance in healthy individuals; seek advice with heart disease.

Heart Block

• First Degree: Delayed conduction, every atrial impulse leads to ventricular contraction.
• Second Degree:
  • Mobitz Type 1 (Wenckebach): Progressive PR prolongation.
  • Mobitz Type 2: Set ratio of P waves to QRS complexes, risk of asystole.
• Third Degree: Complete disassociation between P waves and QRS complexes.

Bradycardias

• Definition: Heart rate < 60 bpm.
• Causes: Medications, heart block, sick sinus syndrome.
• Risk of Asystole: In certain types of heart block.
• Management: Intravenous atropine, ionotropes, temporary pacing, permanent pacemaker.

Conclusion

• Importance of the "testing effect" for longer information retention.
• Zero to Finals offers resources for effective exam preparation and knowledge testing.