Monarch Disease Ontology identifier MONDO_0000468 (third-degree atrioventricular block) is a disorder characterized by an electrocardiographic finding of complete failure of atrial electrical impulse conduction to the ventricles. This is manifested on the ECG by disassociation of atrial and ventricular rhythms. The atrial rate must be faster than the ventricular rate. (CDISC). Also known as: AV block third degree, atrioventricular block complete, atrioventricular block, third degree, complete AV block, complete atrioventricular block, complete heart block, non-congenital complete atrioventricular block, third degree AV block.