Case:
A 41-year-old man with no prior cardiac history and a history of regular
narrow QRS tachycardia, presenting with frequent paroxysmal
palpitations, was referred to our institution. The tachycardia was
adenosine-sensitive, leading to the acute termination of the
tachycardia. The baseline electrocardiogram was unremarkable. During an
electrophysiology study (EPS), supraventricular tachycardia (SVT) was
easily induced by ventricular extrastimuli. Figure 1 shows a single
ventricular extrastimulus applied from the right ventricular apex (RVa)
during the tachycardia, and this finding was reproducible.