What will you learn?
- what VA block means for the potential diagnosis
- how to be sure the block is permanent
- what can influence VA conduction and block
About this scenario
- Retrograde (or V-A) conduction assessment during all EP studies is essential.
- Absence of retrograde conduction allows to rule out the presence of a retrograde accessory pathway.
- Retrograde conduction must be assessed, first in basal state, then after isoproterenol injection.
- Permanent capture of the ventricle (V) is mandatory in order to assess retrograde conduction.
- Pacing the ventricle at low rates (cycle length at 800-700 ms) is mandatory to correctly assess the retrograde conduction, in order to avoid being below the retrograde refractory period of the AV node.
- Assessing the regularity of Atrio-Atrial (A-A) intervals in sinus rhythm, and after V pacing, allows to confirm the absence of retrograde (V-A) conduction.
- Assessing the absence of modification of the atrial activation pattern inside the coronary sinus, first in sinus rhythm, and after V pacing, allows to confirm the absence of retrograde (V-A) conduction.
![](https://cdn.prod.website-files.com/6556498c64dd04b09862251a/65e8b264e6829380304d5115_65e8b1ea252e752d1fc5e30a_63b441a7cbfcf989b92bf53c_L-FHbaVI30z7JxJjGnmaXa0mFktPcbnt8f4tsST3BvI.jpeg)