This week’s electrogram interpretation:
What is observed in the following electrogram?
The ablation catheter is positioned in the LIPV during a pulmonary vein isolation procedure.
Answer
Exit block – AT within the pulmonary vein.
Notice the pulmonary vein activation on the ablation catheter. This is atrial tachycardia within the vein. This tachycardia was induced after pulmonary vein isolation. Atrial tachycardia from the pulmonary vein is a trigger for atrial fibrillation. However, this activity in the vein is not conducting to the atrium – the atrium is still in a paced rhythm demonstrating exit block.
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For more information: EP Essentials – Understanding EP: A Comprehensive Approach – section on atrial fibrillation.
