That depends on how you interpret the very first atrial signal after theRV- pacing stops (three pacing beats were showing here). If you think itis an ectopic activation,and it is similar to all the following atrial signals inthe run,then you can say this is A-Tach.Hold on! Before you can say that for sure,you need to rule out thepossibilities of any reentry type tachycardia. First,A-Tach is not usuallyinitiated by the PES. (But we do see cases where PES initiates an A-Tach.So this discrepancy alone is not strong enough to rule out A-Tach in thiscase.)Second,lets carefully check the three RV-pacing beats. You mayimmediately find that there is a retrograde conduction block already. TheVA interval is not fixed. It becomes longer and longer (Wenckebachblock). Just imagine the third $1 has also successfully made theretrograde conduction albeit with a delay (S1-A interval = 490ms),andonly after that does the tachycardia start. Then you will realize that thistachycardiais not an A-Tach because the very first atrial signal after theRV- pacing is not an ectopic beat.
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