His bundle recordings: their contribution to the understanding of human electrophysiology.

His bundle electrocardiography has increased our understanding of the electrophysiology of the conducting system and has confirmed a number concepts which evolved from analysis of surface electrocardiograms. Electrophysiologic evaluation of conduction disease in the cardiac catheterization laboratory has become an accepted diagnostic procedure in determining the site of atrioventricular and ventriculo-atrial block as well as in the evaluation of patients with pre-excitation resulting from conduction through Kent and James bundles. Recent reports suggest that His bundle electrograms may prove to be of clinical and therapeutic significance in determining the site of re-entry in patients with PSVT as well as in determining the short-term prognosis of patients with acute myocardial infarction complicated by incomplete bundle branch block. As our knowledge and understanding of the basic mechanisms, specific therapy, and prognosis of cardiac arrhythmias are expanded, the data derived from His bundle electrocardiography will become more useful in the clinical practice of cardiology.