Arrhythmic complications management

Arrhythmic complications management

Arrhythmic complications management

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Arrhythmia Overview - The Heart's Glitches

  • Timing is key: Risk is highest in the first 48 hours post-MI.
    • Acute Phase (< 48 hrs): Due to ischemia, electrolyte shifts, and reperfusion injury.
    • Late Phase (> 48 hrs): Arises from scar tissue formation and ventricular remodeling, creating re-entrant circuits.

ECG progression to ventricular fibrillation post-MI

Ventricular fibrillation (V-fib) is the most common cause of sudden cardiac death in the immediate hours following an acute MI.

Bradyarrhythmias & AV Blocks - The Slowdown

  • Sinus Bradycardia: Rate < 60 bpm. Often benign (athletes) or drug-induced (β-blockers, CCBs).
  • AV Blocks: Delay or interruption of atrial impulse to ventricles.
    • 1st Degree: Fixed, prolonged PR interval (> 0.20s).
    • 2nd Degree, Mobitz I (Wenckebach): Progressively lengthening PR until a beat is dropped. 📌 "Longer, longer, longer, DROP!"
    • 2nd Degree, Mobitz II: Constant PR interval with randomly dropped beats. High risk of progressing to 3rd degree.
    • 3rd Degree (Complete): Complete dissociation of P waves and QRS complexes. Requires urgent pacing.

ECG: Third-degree AV block with junctional escape rhythm

⭐ In inferior MIs, AV blocks (especially 1st-degree and Mobitz I) are common due to RCA ischemia affecting the AV node. These often resolve with reperfusion.

Ventricular Arrhythmias - Dangerously Fast Beats

  • Core Principle: Assess for a pulse and hemodynamic stability to guide management. Wide QRS complex tachycardia is treated as VT until proven otherwise.
  • Types & ECG:
    • Ventricular Tachycardia (VT): Organized, wide QRS (>0.12s). Can be monomorphic or polymorphic.
    • Ventricular Fibrillation (VF): Disorganized, chaotic rhythm with no identifiable QRS. No cardiac output.

ECG: Monomorphic VT degenerating into VF

⭐ For Torsades de Pointes (polymorphic VT with a long QT interval), the first-line treatment is IV Magnesium Sulfate, not standard VT antiarrhythmics.

Atrial Fibrillation - Irregularly Irregular

ECG showing Atrial Fibrillation with key features labeled

  • Hallmark: Irregularly irregular rhythm with absent P waves & variable ventricular rate.
  • Acute Management (Unstable): Immediate synchronized cardioversion.
  • Stable Management: Focus on rate control & anticoagulation.
    • Rate Control: β-blockers (metoprolol) or non-DHP CCBs (diltiazem). Goal HR < 110 bpm.
    • Anticoagulation: Guided by CHA₂DS₂-VASc score for stroke prevention.
      • Score ≥ 2 (men) or ≥ 3 (women) → DOACs (e.g., apixaban) > warfarin.

⭐ The CHA₂DS₂-VASc score, not the presence of symptoms, dictates the need for chronic anticoagulation to prevent ischemic stroke.

High‑Yield Points - ⚡ Biggest Takeaways

  • Sinus bradycardia is treated with atropine only if it causes hypotension or altered mental status.
  • Atrial fibrillation requires rate control (beta-blockers) and risk-stratified anticoagulation.
  • Ventricular fibrillation and pulseless VT are shockable rhythms requiring immediate defibrillation.
  • For stable VT, use antiarrhythmics like amiodarone; for unstable VT with a pulse, use synchronized cardioversion.
  • High-degree AV blocks (Mobitz II, third-degree) demand transcutaneous pacing, likely followed by a permanent pacemaker.

Practice Questions: Arrhythmic complications management

Test your understanding with these related questions

A 39-year-old woman is brought to the emergency department 30 minutes after her husband found her unconscious on the living room floor. She does not report having experienced light-headedness, nausea, sweating, or visual disturbance before losing consciousness. Three weeks ago, she was diagnosed with open-angle glaucoma and began treatment with an antiglaucoma drug in the form of eye drops. She last used the eye drops 1 hour ago. Examination shows pupils of normal size that are reactive to light. An ECG shows sinus bradycardia. This patient is most likely undergoing treatment with which of the following drugs?

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Flashcards: Arrhythmic complications management

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Medi-_____ is state/federal assistance for people with limited income/resources

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Medi-_____ is state/federal assistance for people with limited income/resources

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