“…We had previously hypothesized that these recurrences might be mainly due to vasodilatation [9]. This hypothesis was supported by our previous study in which we found that during DDD paced ATP-test, lower systolic blood pressure (BP) was observed in patients who remained symptomatic under temporary pacing [10]. Considering the role of endogenous adenosine in NMS [11,12], remaining symptoms under paced ATP-test might be associated with higher syncope recurrence due to vasodilatation.…”