Ventricular tachycardia arising from His-bundle.

During tachycardia, His-bundle potentials preceded Purkinje potentials. When the radiofrequency application was performed at a site where Purkinje potentials could be recorded slightly more peripherally than His-bundle potentials, tachycardia temporarily stopped, but was quickly followed by tachycardia with left-axis deviated because of the complication of the left anterior fascicular block.