T. Yamashita et al., INCIDENCE OF INDUCED ATRIAL FIBRILLATION FLUTTER IN COMPLETE ATRIOVENTRICULAR-BLOCK - A CONCEPT OF ATRIAL-MALFUNCTIONING ATRIO-HISIAN BLOCK/, Circulation, 95(3), 1997, pp. 650-654
Background Atrial fibrillation/flutter (Af) has been considered to occ
ur coincidentally with atrioventricular (AV) block. However, a case wi
th complete AV block was reported to histologically show fibrotic chan
ges solely in the atrial muscles but neither in the AV node nor in the
His bundle, indicating a possible relation between AV block and atria
l tachyarrhythmias. To test a hypothesis that AV block and Af are caus
ally interrelated, we investigated the incidence and electrophysiologi
cal characteristics of Af in complete AV block. Methods and Results Fo
rty-two patients with persistent complete AV block underwent the elect
rophysiological study. Patients with spontaneous/electrically induced
Af were compared with the other patients with respect to their electro
physiological variables. Of the 42 patients, Af was transiently induce
d by electrical stimulation in 5 patients (11.9%), while persistent Af
was observed in 2 patients (4.8%, AH and HV block). AV block in the 5
patients with induced Af was invariably due to AH block. AH block com
plicated by persistent/induced Af was marked by relatively short RR in
tervals, significantly short junctional recovery time, and impaired in
tra-atrial conduction. Conclusions Electrically induced Af in complete
AV block was associated frequently with complete AH block. These pati
ents were characterized differently from the commonly recognized AV bl
ock and therefore may stand as a unique subgroup of AH block.