Atrioventricular block Second degree atrioventricular block 2012-04-11T07:22:35Z UMLS:C0264906 HP:0011706 An intermittent atrioventricular block with failure of some atrial impulses to conduct to the ventricles, i.e., some but not all atrial impulses are conducted through the atrioventricular node and trigger ventricular contraction. SNOMEDCT_US:195042002