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5-2. Lesson 5 (cont) Supraventricular Arrhythmias

Topics of Study:

  1. Premature atrial complexes
  2. Premature junctional complexes
  3. Atrial fibrillation
  4. Atrial flutter
  5. Ectopic atrial tachycardia and rhythm
  6. Multifocal atrial tachycardia
  7. Paroxysmal supraventricular tachycardia
  8. Junctional rhythms and tachycardias


Premature atrial complexes

Premature junctional complexes

Atrial Fibrillation (A-fib)

image 05-26

Atrial Flutter (A-flutter):

image 05-27

Ectopic Atrial Tachycardia and Rhythm

Multifocal Atrial Tachycardia (MAT) and rhythm

image 05-29

Paroxysmal Supraventricular Tachycardia (PSVT)

Junctional Rhythms and Tachycardias

Junctional Escape Beats

These are passive, protective beats originating from subsidiary pacemaker cells in the AV junction (usually in the Bundle of His). The pacemaker's basic firing rate is 40-60 bpm; junctional escapes are protective events that occur whenever the primary pacemaker (i.e., sinus node) defaults or the AV node blocks the atrial impulse. The ECG strip shows intermittent sinus slowing with two junctional escapes.

image 07-01

Junctional Escape Rhythm

A Junctional Escape Rhythm is a sequence of 3 or more junctional escapes occurring by default at a rate of 40-60 bpm. The 12-lead ECG shown below illustrates a junctional escape rhythm in a well-trained athlete whose resting sinus rate is slower than the junctional rate. Retrograde P waves are hidden in the ST-T waves and best seen in leads II, III, and aVF.

image 03-07

Accelerated Junctional Rhythm

This is an active junctional pacemaker rhythm caused by events that perturb pacemaker cells (e.g., ischemia, drugs, and electrolyte abnormalities). The rate is 60-100 bpm).

image 03-14

Nonparoxysmal Junctional Tachycardia

This usually begins as an accelerated junctional rhythm but the heart rate gradually increases to > 100 bpm. There may be AV dissociation, or retrograde atrial capture may occur. Ischemia (usually from right coronary artery occlusion) and digitalis intoxication are the two most common causes. In the example below junctional tachycardia is seen with ('B') and without exit block ('A').

image 05-19

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