Ventricular tachycardia originating from the His bundle: A case report

Figure 1 12-lead electrocardiogram obtained during a transesophageal electrophysiological study. For the first several beats, the electrocardiogram pattern corresponded to a right-bundle-branch block and left-posterior-branch block, with a rate of 187 bpm. The pattern subsequently spontaneously changed to another form with a rate of 202 bpm, showing rS in lead V1, positive QRS polarity in leads I, II and aVL and negative QRS polarity in leads II, III and aVF. A few seconds later, sinus rhythm appeared and captured the His bundle potential. The next atrial premature contraction with a long interval induced a subsequent episode of ventricular tachycardia, similar to the first several beats. The ventricular potential was always matched with the His potential but was not related to the atrial potential; that is, the AA and VV intervals were constant.