Premature atrial contraction

Premature atrial contractions

  • QRS appears early
  • P wave different morphology
  • Incomplete compensatory pause

Premature ventricular contraction

Premature ventricular contractions

  • Differing morphology QRS w/o proceeding P wave
  • Full compensatory pause
  • Typically large T wave w/ opposite polarity of QRS

Supraventricular tachycardia

Supraventricular tachycardia

  • Sudden start and stop
  • Narrow complex
  • Usually do not see P wave (may be retrograde P wave in T wave)
  • No HR variability

1° AV block

AV Block Degrees

  • PR prolongation >0.2 sec

2° AV block

  • Mobitz Type I (Wenckebach)
    • Increasing PR intervals prior to dropped QRS
  • Mobitz Type II
    • Intermittently non-conducted P waves not preceded by PR prolongation 

3° AV block

  • No apparent relationship between P waves and QRS complexes

Atrial activity

 *Atrial activity is marked by blue and ventricular activity is marked by red. Note that some P waves follow the QRS = dissociation!

Junctional ectopic tachycardia

Junctional ectopic tachycardia

  • Narrow complex tachycardia
  • P waves not discernible, are dissociated from the QRS, or show retrograde conduction
  • Typically "ramps up and ramps down"
  • No HR variability