T. Serita et al., EVIDENCE OF 3 CLINICAL SUBGROUPS IN PATIENTS WITH DUAL ATRIOVENTRICULAR NODAL PATHWAYS, The American journal of the medical sciences, 314(1), 1997, pp. 11-16
We attempted to test the hypothesis that dual atrioventricular (A-V) n
odal pathways with second-degree atrioventricular block (2nd A-V block
) present as a different clinical entity from those with A-V nodal ree
ntranttachycardia (AVNRT). By evaluation with Holter monitoring (2.9 /- 2.5 recordings/patient) and 12-lead electrocardiogram (11.9 +/- 11.
6), 177 patients with dual A-V nodal pathways could be divided into th
ree subgroups. Thirty-two patients had 2nd A-V block only (2nd A-V blo
ck group), 57 had AVNRT only (AVNRT group), 88 had neither 2nd A-V blo
ck nor AVNRT (silent group), and none had 2nd A-V block and AVNRT both
. Electrophysiologic studies showed that the atrio-His interval was si
gnificantly greater (P < 0.0001) and the maximal 1:1 atrioventricular
conduction rate was lower (P < 0.0001) in the 2nd A-V block group than
in the other two groups. These differences were nullified after the a
dministration of atropine. These results suggest that patients with du
al A-V nodal pathways can be classified into three clinical subgroups
based on the presence of either 2nd A-V block or AVNRT. We suggest als
o that patients of the 2nd A-V block group may have a more augmented v
agal tone on the A-V node than the other two groups.