Introduction: The diagnostic role of ajmaline challenge in patients with unexplained syncope and a negative workup, including normal basal ECG, is unclear.
Methods: Patients with unexplained syncope and a negative workup were enrolled. Conduction disturbances on ECG were not considered as an exclusion criteria. EPS was performed and basal HV interval was measured. In the presence of a HV interval >70 msec the study was interrupted and a PM was implanted. If HV interval was ? 70 msec, ajmaline (1 mg/Kg over 2’) was infused. A prolongation ?100 msec was considered as diagnostic, and patients were implanted with a PM, otherwise an ILR was positioned.
Results: Sixteen patients were enrolled since September 2014 to March 2015 (figure 1). Seven had normal ECG. Of them, none had a basal HV >70 msec. Three patients had pathological response after ajmaline challenge.
Conclusions: Ajmaline challenge is an useful tool to unmask the presence of a conduction disease in patients with unexplained syncope and negative workup, even in patients without conduction disturbances on basal ECG. Larger population is required to validate this hypothesis.