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 21 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 21 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.