The arrhythmia is intermittent and at first glance might easily have been interpreted as supraventricular with right bundle branch block aberrancy based on the appearance of the QRS complexes and their failure to meet any of the Brugada morphologic criteria. However, there are sinus P waves which precede the narrow complex beats and march through the wide complex beats. This arrhythmia is another example of fascicular tachycardia. Try to identify the P waves before proceeding.