Wide QRS complex tachycardia due to typical atrial flutter with accessory pathway conduction

A 62-year-old male patient was admitted with regular wide QRS complex tachycardia. After ajmaline administration, the heart rate slowed down disclosing atrial flutter with variable QRS morphologies. Electrocardiography after conversion to sinus rhythm showed narrow QRS complexes. Decremental atrial stimulation during electrophysiological study caused progressive pre-excitation. Spontaneously, typical atrial flutter occurred with pre-excited QRS complexes. Both accessory pathway and atrial flutter were ablated in the same session.