Figure 1.

The sequence of ventricular activation impacts the appearance of J wave in a pseudo-electrocardiogram recorded from coronary-perfused canine right ventricular wedge preparation. (a) Stimulation of the endocardial (Endo) surface causes the epicardial (Epi) surface to be activated last; (b) stimulation of the epicardial surface activates it before the endocardial surface; (c) endocardial activation at different locations can cause the J wave to occur at the end of the QRS, manifesting as slurred (left panel) or notched (right panel) QRS.