This week’s electrogram interpretation:
What is observed in the following electrogram?
Answer
AV Wenckebach
- Atrial decremental pacing is occurring via CS 9,10. Notice the narrow QRS complex; therefore, we are not pacing/capturing the ventricle. There is also saturation of the CS 9,10 channel.
- Atrial capture is observed by immediate atrial signal following the pacing artifact in the adjacent channels.
- Crossover is observed right before AV block. Notice that the next pacing artifact and atrial capture is observed before the V from the previous pacing impulse.
- The next impulse is delivered and captures the atrium, but does not conduct to the ventricle = AV Block.
- The next impulse is able to capture the atrium and conduct to the ventricles.
- This is the normal pattern of AV Wenckebach…. the AV will increasingly prolong until blocked. At which point, the next AV interval will be shorter again and the pattern continues.
Please subscribe for a weekly link to the newest blog post.
If you like this, find hundreds of electrograms to interpret in our Understanding EP workbook – included in the Understanding EP book set.
For more information: EP Essentials – Understanding EP: A Comprehensive Approach
