Electrocardiography of Atrioventricular Block

Abstract

Delayed atrioventricular (AV) conduction most commonly occurs in the AV node, resulting from AH prolongation on an intracardiac electrocardiogram and PR prolongation on a surface electrocardiogram. AV conduction may be blocked in a 2:1 manner, with a normal PR interval and wide QRS suggesting infranodal disease, whereas a prolonged PR interval and narrow QRS are more suggestive of AV nodal disease. Block within the His is suspected when there is 2:1 AV block with normal PR and QRS intervals. Complete heart block occurs when the atrial rhythm is totally independent of a junctional or lower escape rhythm.

Keywords: Atrioventricular delay; Atrioventricular node; Complete heart block; Dual atrioventricular node physiology; Second degree type 1 atrioventricular block; Second degree type 2 atrioventricular block; Third degree atrioventricular block; Wenckebach.