Academic Day Seminars

ADS – Atrial fibrillation

This was a great ADS about all things electrical about the heart. Below are some tidbits I picked up:

Afib ECG features:

  • Loss of distinct P waves
  • Chaotic activity of atria
  • Irregular R-R intervals
  • Narrow QRS complex

Afib has abnormal electrochemical activity causing ectopic beats: enhanced automaticity, early after depolarization and delayed after depolarization

Classification of Afib:

Paroxysmal: AF that terminates spontaneously or with intervention within 7 days of onset, episodes may recur with variable frequency

Persistent: Continuous AF that is sustained for >7 days

Long-standing persistent: Continuous AF that is sustained for >12 months

Permanent: The patient and clinician make a joint decision to stop further attempts to restore and/or maintain sinus rhythm since control of rhythm is no longer achievable or desirable

  • If they have long term AF w/o treatment then even when we shock them we are less likely to send them into normal sinus rhythm

Simialrities between afib & atrial flutter:

  • Supraventricular tachyarrhythmia
  • Some electrical impulses reach the ventricle, causing premature ventricularcontractions

Difference between afib &atrial flutter:

  • Afib: atrium is “twitching” and is not contracting at the same time, irregular pattern
  • Atrial flutter: atrium is beating together in a very rapid rate, regular pattern

Refer to the CCS guidelines for acute management, unstable AF, stable AF management and long term management.

Who needs to be anticoagulated? 2-3-4 rule

  • If the patient is in AF for >2 days (or unknown), we must anticoagulate with warfarin for 3 weeks (INR 2-3) prior to cardioversion, and continue anticoagulation for at least 4 weeks post cardioversion

Rate vs Rhythm:

  • Favours rate control:
    • Persistent AF
    • Less symptomatic
    • Age≥65
    • Hypertension
    • No history of HF
    • Previous antiarrhythmic drug failure
    • Patient preference
  • Favours Rhythm control:
    • Paroxysmal/New AF
    • Symptomatic
    • Age<65
    • No Hypertension
    • HF clearly exacerbated by AF
    • No previous antiarrhythmic drug failure
    • Patient preference

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