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Introduction to Atrial Rhythms


ventricular rhythm heart illustration

This page provides an introduction to atrial rhythms and links to training materials on this website.

Atrial rhythms originate in the atria rather than in the SA node. The P wave will be positive, but its shape can be different than a normal sinus rhythm because the electrical impulse follows a different path to the AV (atrioventricular) node. These EKG differences are covered on our atrial rhythms training module as well as in practice strips which are available via a link in the right column. Atrial rhythms are classified as:

  • Atrial Fibrillation (afib)
  • Atrial Flutter
  • Multifocal Atrial Tachycardia
  • Premature Atrial Complex
  • Supraventricular Tachycardia
  • Wandering Atrial Pacemaker
  • Wolff-Parkinson-White Syndrome

Atrial Rhythm Categories

Atrial Fibrillation

Atrial Fibrillation EKG tracing

Irritable sites in the atria fire very rapidly, between 400-600 bpm. This very rapid pacemaking caused the atria to quiver. The ventricles beat at a slower rate due to the AV node's blocking of some of the atrial impulses.

Atrial Flutter

Atrial Flutter EKG tracing

There are two types of atrial flutter. Type I (also called classical or typical) has a rate of 250-350 bpm. Type II (also called non-typical) are faster, ranging from 350-450 bpm. EKG tracings will show tightly spaced waves or saw-tooth waveforms (F-waves).

Multifocal Atrial Tachycardia

Multifocal Atrial Tachycardia EKG tracing

When multifocal atrial tachycardia occurs, multiple (non-SA) sites are firing impulses. The P waves will vary in shape and at least three different shapes can be observed. The PR Interval varies. Ventricular rhythm is irregular.

Premature Atrial Complex

Premature Atrial Complex EKG tracing

This occurs when an ectopic sites within the atria fires an impulse before the next impulse from the SA node. If the ectopic site is near the SA node, the P wave will likely have a shape similar to a sinus rhythm. But this P wave will occur earlier than expected.

Supraventricular Tachycardia

Supraventricular Tachycardia EKG tracing

This term covers three types of tachycardia that originate in the atria, AV junction or SA node.

Wandering Atrial Pacemaker

 rhythm EKG tracing

Wandering atrial pacemaker is an irregular rhythm. In is similar to multifocal atrial tachycardia but the heart rate is under 100 bpm. P waves are present but will vary in shape.

Wolff-Parkinson-White Syndrome

 rhythm EKG tracing

This occurs when the impulse travels between the atria and ventricles via an abnormal path, called the bundle of Kent. The impulse, not being delayed by the AV node, can cause the ventricles to contract prematurely. EKG characteristics include a shorter PR Interval, longer QRS complex and a delta wave.

Click To Begin Atrial Rhythms Training Module


Atrial Dysrhythmias

Thomas E. O'Brien

Learning Objectives

At the conclusion of this training module the reader will be able to:

  • Recall and apply the 5-steps of heart rhythm interpretation
  • Recognize the difference between regular and irregular rhythms
  • Recall the normal range for PR interval and QRS complex
  • Recognize the features and qualifying criteria for the following complexes and rhythms:
    • Premature Atrial Complexes
    • Wandering Atrial Pacemaker Rhythm
    • Multifocal Atrial Tachycardia
    • Atrial Flutter
    • Atrial Fibrillation

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