JSS, 28 years old, Caucasian man with history of recurrent paroxysmal palpitations since age 14 years. Several hospitalizations in the emergency room with recording of regular tachycardia with a borderline-broad complex.
Current admission by dyspnea and precordial pain with recording of ventricular tachycardia with cycle of 500 ms (120 bpm) and ECG with atypical RBBB pattern + Prominent Anterior QRS forces and superior axis deviation: LAFB-like type (suggestive of anterior divisional tachycardia).
Little response to treatment with IV amiodarone. Several attempts of cardioversion were successful immediately and early recurrence of tachycardia. We chose to perform electrophysiology study.
Which is the diagnosis of the event?
Which is the mechanism?
Which is probable circuit used as descending pathway and ascending direction?