Disturbances of Atrioventricular Conduction

Abstract

Rather than a series of discrete elements, the AV conduction system is best viewed as a continuum of variably conductive tissues extending from the sinoatrial nodal/atrial junction to the Purkinje network/ventricular muscle cell junction. However, from a practical standpoint, electrophysiologists generally compartmentalize different segments of this continuum to facilitate ease of study and analysis. Consequently, study of normal and abnormal AV conduction involves an analyses of impulse conduction through the 1) sinoatrial node/atria; 2) AV node; 3) His bundle; and) infra-Hisian (His-Purkinje) system/ ventricular myocardium. From a clinical standpoint, conduction disturbances residing below the central fibrous body within the His bundle and His-Purkinje system have the most pathological significance as they are often associated with clinically significant structural heart disease. In selected patients, intracardiac electrophysiology study may assist in the precise localization of the conduction disturbance thereby allowing the identification and differentiation of symptomatic high-risk patients from low-risk patients, especially when non-invasive testing has not proved useful.