Physiologic Differentiation Between Selective His Bundle, Nonselective His Bundle and Septal Pacing.

His bundle (HB) pacing is an increasingly popular method of physiologic ventricular pacing. The electrocardiographic hallmark of physiologic pacing is the preservation or restoration of physiologic activation times in the left ventricle-a principle of paramount diagnostic importance. The current review focuses on the differentiation between 3 possible capture types when the pacing lead is placed in the HB region: selective HB capture when only HB is activated, nonselective HB capture when there is simultaneous activation of the adjacent right ventricular septal (RVS) myocardium, and selective RVS capture when HB is not activated at all but only septal myocardium.