Atrial Rhythms

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    53 year old female with heart palpitations.

    53 year old female with heart palpitations.

    Questions

    Question 1: The RR intervals seem irregular in this EKG. Why is this not atrial fibrillation?

    Question 2: What is the physiologic explanation for regularly irregular conduction during atrial flutter as seen in this EKG?

    Key Findings

    - Atrial flutter with variable conduction

    Coding for Boards

    - Atrial flutter

    Answers

    Question 1: Careful inspection of the intervals reveals that they are regularly irregular. Also, the atrial deflections are in a regular, saw-toothed pattern, such as seen in atrial flutter.

    Question 2:  Usually atrial flutter conducts with a 2:1 pattern. Occasionally, atrial flutter will conduct in a 2:1 pattern through one portion of the AV node, and in a different pattern through another portion of the AV node. These different types of conduction are thought to occur at different levels of the AV node. Thus, this pattern is called multi-level block.