Paced Rhythms

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    64 year old female with a history of pacemaker.

    64 year old female with a history of pacemaker.

    Key Findings

    -Underlying atrial fibrillation

    -Ventricular pacing with a vector suggestive of biventricular pacing 

    Coding for the Boards

    - Atrial fibrillation
    - Paced morpohology consistent with biventricular pacing

    Answers

    Discussion: When the paced QRS is positive in V1 and negative in limb lead I, this is fairly specific for cardiac resynchronization therapy. Do not forget to code the underlying atrial rhythm which is best seen in V3 (atrial fibrillation).