Syncope ?

A 41-year-old female patient presenting with syncope without a clear prodrome. The episode occurred during exertion, although the circumstances are not entirely clear. She reports experiencing a vague presyncopal sensation beforehand, without definite palpitations.

The HV interval was normal at 67 ms. No ventricular tachycardia was induced. Only a 1:1 tachycardia with a long VA interval was observed, with a cycle length of 316 ms. Overdrive pacing at 300 ms was technically challenging but was eventually successful, yielding a PPI–CL of 220 ms and a pseudo-VAAV response. These findings are consistent with AVNRT, most likely the slow–slow type.