Puzzle 2004 1 28
Authors: J.M.E. van Dijen, L.V.A. Boersma, P.J. van Hartingsveldt, E.F.D. Wever.
A55-year-old female had been experiencing episodes of palpitations for 30 years. These palpitations could start at any moment of the day. Normally, these episodes were self-limiting. Last year, however, she visited the emergency ward because her complaints did not terminate spontaneously, although after intravenous administration of adenosine they resolved. The ECGs during sinus rhythm and during palpitations are shown in figure 1 and figure 2 A and B, respectively. Structural heart disease was ruled out, and she was referred for electrophysiological study (EPS) and catheter ablation using radio-frequency current (RFCA). During EPS, two types of narrow-QRS tachycardia were inducible as shown in figure 2A and B. What would be the underlying mechanism of these arrhythmias and what therapy would you suggest? Answer